/* Copyright (C) 2005 The cairomm Development Team
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
#ifndef __CAIROMM_CONTEXT_H
#define __CAIROMM_CONTEXT_H
#include <vector>
#include <utility>
#include <cairomm/surface.h>
#include <cairomm/fontface.h>
#include <cairomm/matrix.h>
#include <cairomm/pattern.h>
#include <cairomm/path.h>
#include <cairomm/scaledfont.h>
#include <cairomm/types.h>
#include <valarray>
#include <vector>
#include <cairo.h>
namespace Cairo
{
/**
* Context is the main class used to draw in cairomm. It contains the current
* state of the rendering device, including coordinates of yet to be drawn
* shapes.
*
* In the simplest case, create a Context with its target Surface, set its
* drawing options (line width, color, etc), create shapes with methods like
* move_to() and line_to(), and then draw the shapes to the Surface using
* methods such as stroke() or fill().
*
* Context is a reference-counted object that should be used via Cairo::RefPtr.
*/
class Context
{
protected:
explicit Context(const RefPtr<Surface>& target);
public:
/** Create a C++ wrapper for the C instance. This C++ instance should then be
* given to a RefPtr.
*
* @param cobject The C instance.
* @param has_reference Whether we already have a reference. Otherwise, the
* constructor will take an extra reference.
*/
explicit Context(cairo_t* cobject, bool has_reference = false);
Context(const Context&) = delete;
Context& operator=(const Context&) = delete;
static RefPtr<Context> create(const RefPtr<Surface>& target);
virtual ~Context();
/** Makes a copy of the current state of the Context and saves it on an
* internal stack of saved states. When restore() is called, it will be
* restored to the saved state. Multiple calls to save() and restore() can be
* nested; each call to restore() restores the state from the matching paired
* save().
*
* It isn't necessary to clear all saved states before a cairo_t is freed.
* Any saved states will be freed when the Context is destroyed.
*
* @sa restore()
*/
void save();
/** Restores cr to the state saved by a preceding call to save() and removes
* that state from the stack of saved states.
*
* @sa save()
*/
void restore();
/** Sets the compositing operator to be used for all drawing operations. See
* Operator for details on the semantics of each available compositing
* operator.
*
* @param op a compositing operator, specified as a Operator
*/
void set_operator(Operator op);
/** Sets the source pattern within the Context to source. This Pattern will
* then be used for any subsequent drawing operation until a new source
* pattern is set.
*
* Note: The Pattern's transformation matrix will be locked to the user space
* in effect at the time of set_source(). This means that further
* modifications of the current transformation matrix will not affect the
* source pattern.
*
* @param source a Pattern to be used as the source for subsequent drawing
* operations.
*
* @sa Pattern::set_matrix()
* @sa set_source_rgb()
* @sa set_source_rgba()
* @sa set_source(const RefPtr<Surface>& surface, double x, double y)
*/
void set_source(const RefPtr<const Pattern>& source);
/** Sets the source pattern within the Context to an opaque color. This
* opaque color will then be used for any subsequent drawing operation until
* a new source pattern is set.
*
* The color components are floating point numbers in the range 0 to 1. If
* the values passed in are outside that range, they will be clamped.
*
* @param red red component of color
* @param green green component of color
* @param blue blue component of color
*
* @sa set_source_rgba()
* @sa set_source()
*/
void set_source_rgb(double red, double green, double blue);
/** Sets the source pattern within the Context to a translucent color. This
* color will then be used for any subsequent drawing operation until a new
* source pattern is set.
*
* The color and alpha components are floating point numbers in the range 0
* to 1. If the values passed in are outside that range, they will be
* clamped.
*
* @param red red component of color
* @param green green component of color
* @param blue blue component of color
* @param alpha alpha component of color
*
* @sa set_source_rgb()
* @sa set_source()
*/
void set_source_rgba(double red, double green, double blue, double alpha);
/** This is a convenience function for creating a pattern from a Surface and
* setting it as the source
*
* The x and y parameters give the user-space coordinate at which the Surface
* origin should appear. (The Surface origin is its upper-left corner before
* any transformation has been applied.) The x and y patterns are negated and
* then set as translation values in the pattern matrix.
*
* Other than the initial translation pattern matrix, as described above, all
* other pattern attributes, (such as its extend mode), are set to the
* default values as in Context::create(const RefPtr<Surface>& target). The
* resulting pattern can be queried with get_source() so that these
* attributes can be modified if desired, (eg. to create a repeating pattern
* with Pattern::set_extend()).
*
* @param surface a Surface to be used to set the source pattern
* @param x User-space X coordinate for surface origin
* @param y User-space Y coordinate for surface origin
*/
void set_source(const RefPtr<Surface>& surface, double x, double y);
/** Sets the tolerance used when converting paths into trapezoids. Curved
* segments of the path will be subdivided until the maximum deviation
* between the original path and the polygonal approximation is less than
* tolerance. The default value is 0.1. A larger value will give better
* performance, a smaller value, better appearance. (Reducing the value from
* the default value of 0.1 is unlikely to improve appearance significantly.)
* The accuracy of paths within Cairo is limited by the precision of its
* internal arithmetic, and the prescribed @tolerance is restricted to the
* smallest representable internal value.
*
* @param tolerance the tolerance, in device units (typically pixels)
*/
void set_tolerance(double tolerance);
/** Set the antialiasing mode of the rasterizer used for drawing shapes. This
* value is a hint, and a particular backend may or may not support a
* particular value. At the current time, no backend supports
* Cairo::ANTIALIAS_SUBPIXEL when drawing shapes.
*
* Note that this option does not affect text rendering, instead see
* FontOptions::set_antialias().
*
* @param antialias the new antialiasing mode
*/
void set_antialias(Antialias antialias);
/** Set the current fill rule within the cairo Context. The fill rule is used
* to determine which regions are inside or outside a complex (potentially
* self-intersecting) path. The current fill rule affects both fill() and
* clip(). See FillRule for details on the semantics of each available fill
* rule.
*
* The default fill rule is Cairo::FILL_RULE_WINDING.
*
* @param fill_rule a fill rule, specified as a FillRule
*/
void set_fill_rule(FillRule fill_rule);
/** Sets the current line width within the cairo Context. The line width
* specifies the diameter of a pen that is circular in user-space, (though
* device-space pen may be an ellipse in general due to scaling/shear/rotation
* of the CTM).
*
* Note: When the description above refers to user space and CTM it refers to
* the user space and CTM in effect at the time of the stroking operation,
* not the user space and CTM in effect at the time of the call to
* set_line_width(). The simplest usage makes both of these spaces
* identical. That is, if there is no change to the CTM between a call to
* set_line_width() and the stroking operation, then one can just pass
* user-space values to set_line_width() and ignore this note.
*
* As with the other stroke parameters, the current line cap style is
* examined by stroke(), stroke_extents(), and stroke_to_path(), but does not
* have any effect during path construction.
*
* The default line width value is 2.0.
*
* @param width a line width, as a user-space value
*/
void set_line_width(double width);
/** Sets the current line cap style within the cairo Context. See
* LineCap for details about how the available line cap styles are drawn.
*
* As with the other stroke parameters, the current line cap style is
* examined by stroke(), stroke_extents(), and stroke_to_path(), but does not
* have any effect during path construction.
*
* The default line cap style is Cairo::LINE_CAP_BUTT.
*
* @param line_cap a line cap style, as a LineCap
*/
void set_line_cap(LineCap line_cap);
/** Sets the current line join style within the cairo Context. See LineJoin
* for details about how the available line join styles are drawn.
*
* As with the other stroke parameters, the current line join style is
* examined by stroke(), stroke_extents(), and stroke_to_path(), but does not
* have any effect during path construction.
*
* The default line join style is Cairo::LINE_JOIN_MITER.
*
* @param line_join a line joint style, as a LineJoin
*/
void set_line_join(LineJoin line_join);
#ifndef CAIROMM_DISABLE_DEPRECATED
/**
* Alternate version of set_dash(). You'll probably want to use the one that
* takes a std::vector argument instead.
*
* @deprecated Instead use the version that takes a const dashes parameter.
*/
void set_dash(std::valarray<double>& dashes, double offset);
/** Sets the dash pattern to be used by stroke(). A dash pattern is specified
* by dashes, an array of positive values. Each value provides the user-space
* length of altenate "on" and "off" portions of the stroke. The offset
* specifies an offset into the pattern at which the stroke begins.
*
* If dashes is empty dashing is disabled. If the size of dashes is 1, a
* symmetric pattern is assumed with alternating on and off portions of the
* size specified by the single value in dashes.
*
* It is invalid for any value in dashes to be negative, or for all values to
* be 0. If this is the case, an exception will be thrown
*
* @param dashes an array specifying alternate lengths of on and off portions
* @param offset an offset into the dash pattern at which the stroke should start
*
* @exception
*
* @deprecated Instead use the version that takes a const dashes parameter.
*/
void set_dash(std::vector<double>& dashes, double offset);
#endif //CAIROMM_DISABLE_DEPRECATED
/**
* Alternate version of set_dash(). You'll probably want to use the one that
* takes a std::vector argument instead.
*/
void set_dash(const std::valarray<double>& dashes, double offset);
/** Sets the dash pattern to be used by stroke(). A dash pattern is specified
* by dashes, an array of positive values. Each value provides the user-space
* length of altenate "on" and "off" portions of the stroke. The offset
* specifies an offset into the pattern at which the stroke begins.
*
* Each "on" segment will have caps applied as if the segment were a separate
* sub-path. In particular, it is valid to use an "on" length of 0.0 with
* Cairo::LINE_CAP_ROUND or Cairo::LINE_CAP_SQUARE in order to distributed
* dots or squares along a path.
*
* Note: The length values are in user-space units as evaluated at the time
* of stroking. This is not necessarily the same as the user space at the
* time of set_dash().
*
* If dashes is empty dashing is disabled. If the size of dashes is 1, a
* symmetric pattern is assumed with alternating on and off portions of the
* size specified by the single value in dashes.
*
* It is invalid for any value in dashes to be negative, or for all values to
* be 0. If this is the case, an exception will be thrown
*
* @param dashes an array specifying alternate lengths of on and off portions
* @param offset an offset into the dash pattern at which the stroke should start
*
* @exception
*/
void set_dash(const std::vector<double>& dashes, double offset);
/** This function disables a dash pattern that was set with set_dash()
*/
void unset_dash();
/**
* Sets the current miter limit within the cairo context.
*
* If the current line join style is set to Cairo::LINE_JOIN_MITER (see
* set_line_join()), the miter limit is used to determine whether the lines
* should be joined with a bevel instead of a miter. Cairo divides the length
* of the miter by the line width. If the result is greater than the miter
* limit, the style is converted to a bevel.
*
* As with the other stroke parameters, the current line miter limit is
* examined by stroke(), stroke_extents(), and stroke_to_path(), but does not
* have any effect during path construction.
*
* The default miter limit value is 10.0, which will convert joins with
* interior angles less than 11 degrees to bevels instead of miters. For
* reference, a miter limit of 2.0 makes the miter cutoff at 60 degrees, and
* a miter limit of 1.414 makes the cutoff at 90 degrees.
*
* A miter limit for a desired angle can be computed as: miter_limit =
* 1/sin(angle/2)
*
* @param limit miter limit to set
**/
void set_miter_limit(double limit);
/** Modifies the current transformation matrix (CTM) by translating the
* user-space origin by (tx, ty). This offset is interpreted as a user-space
* coordinate according to the CTM in place before the new call to
* translate. In other words, the translation of the user-space origin
* takes place after any existing transformation.
*
* @param tx amount to translate in the X direction
* @param ty amount to translate in the Y direction
*/
void translate(double tx, double ty);
/** Modifies the current transformation matrix (CTM) by scaling the X and Y
* user-space axes by sx and sy respectively. The scaling of the axes takes
* place after any existing transformation of user space.
*
* @param sx scale factor for the X dimension
* @param sy scale factor for the Y dimension
*/
void scale(double sx, double sy);
/** Modifies the current transformation matrix (CTM) by rotating the
* user-space axes by angle radians. The rotation of the axes takes places
* after any existing transformation of user space. The rotation direction
* for positive angles is from the positive X axis toward the positive Y
* axis.
*
* @param angle angle (in radians) by which the user-space axes will be
* rotated
*/
void rotate(double angle_radians);
/** A convenience wrapper around rotate() that accepts angles in degrees
*
* @param angle_degrees angle (in degrees) by which the user-space axes
* should be rotated
*/
void rotate_degrees(double angle_degres);
/** Modifies the current transformation matrix (CTM) by applying matrix as an
* additional transformation. The new transformation of user space takes
* place after any existing transformation.
*
* @param matrix a transformation to be applied to the user-space axes
*/
void transform(const Matrix& matrix);
/* To keep 1.6.x ABI */
void transform(const cairo_matrix_t& matrix);
/** Modifies the current transformation matrix (CTM) by setting it equal to
* matrix.
*
* @param matrix a transformation matrix from user space to device space
*/
void set_matrix(const Matrix& matrix);
/* To keep 1.6.x ABI */
void set_matrix(const cairo_matrix_t& matrix);
/** Resets the current transformation matrix (CTM) by setting it equal to the
* identity matrix. That is, the user-space and device-space axes will be
* aligned and one user-space unit will transform to one device-space unit.
*/
void set_identity_matrix();
#ifndef CAIROMM_DISABLE_DEPRECATED
/** Transform a coordinate from user space to device space by multiplying the
* given point by the current transformation matrix (CTM).
*
* @param x X value of coordinate (in/out parameter)
* @param y Y value of coordinate (in/out parameter)
*
* @deprecated Use the const version.
*/
void user_to_device(double& x, double& y);
/** Transform a distance vector from user space to device space. This
* function is similar to user_to_device() except that the translation
* components of the CTM will be ignored when transforming (dx,dy).
*
* @param dx X component of a distance vector (in/out parameter)
* @param dy Y component of a distance vector (in/out parameter)
*
* @deprecated Use the const version.
*/
void user_to_device_distance(double& dx, double& dy);
/** Transform a coordinate from device space to user space by multiplying the
* given point by the inverse of the current transformation matrix (CTM).
*
* @param x X value of coordinate (in/out parameter)
* @param y Y value of coordinate (in/out parameter)
*
* @deprecated Use the const version.
*/
void device_to_user(double& x, double& y);
/** Transform a distance vector from device space to user space. This
* function is similar to device_to_user() except that the translation
* components of the inverse CTM will be ignored when transforming (dx,dy).
*
* @param dx X component of a distance vector (in/out parameter)
* @param dy Y component of a distance vector (in/out parameter)
*
* @deprecated Use the const version.
*/
void device_to_user_distance(double& dx, double& dy);
#endif //CAIROMM_DISABLE_DEPRECATED
/** Transform a coordinate from user space to device space by multiplying the
* given point by the current transformation matrix (CTM).
*
* @param x X value of coordinate (in/out parameter)
* @param y Y value of coordinate (in/out parameter)
*/
void user_to_device(double& x, double& y) const;
/** Transform a distance vector from user space to device space. This
* function is similar to user_to_device() except that the translation
* components of the CTM will be ignored when transforming (dx,dy).
*
* @param dx X component of a distance vector (in/out parameter)
* @param dy Y component of a distance vector (in/out parameter)
*/
void user_to_device_distance(double& dx, double& dy) const;
/** Transform a coordinate from device space to user space by multiplying the
* given point by the inverse of the current transformation matrix (CTM).
*
* @param x X value of coordinate (in/out parameter)
* @param y Y value of coordinate (in/out parameter)
*/
void device_to_user(double& x, double& y) const;
/** Transform a distance vector from device space to user space. This
* function is similar to device_to_user() except that the translation
* components of the inverse CTM will be ignored when transforming (dx,dy).
*
* @param dx X component of a distance vector (in/out parameter)
* @param dy Y component of a distance vector (in/out parameter)
*/
void device_to_user_distance(double& dx, double& dy) const;
/** Clears the current path. After this call there will be no current point.
*/
void begin_new_path();
/** Begin a new subpath. Note that the existing path is not affected. After
* this call there will be no current point.
*
* In many cases, this call is not needed since new subpaths are frequently
* started with move_to().
*
* A call to begin_new_sub_path() is particularly useful when beginning a new
* subpath with one of the arc() calls. This makes things easier as it is no
* longer necessary to manually compute the arc's initial coordinates for a
* call to move_to().
*
* @since 1.2
*/
void begin_new_sub_path();
/** If the current subpath is not empty, begin a new subpath. After this call
* the current point will be (x, y).
*
* @param x the X coordinate of the new position
* @param y the Y coordinate of the new position
*/
void move_to(double x, double y);
/** Adds a line to the path from the current point to position (x, y) in
* user-space coordinates. After this call the current point will be (x, y).
*
* If there is no current point before the call to line_to()
* this function will behave as move_to(x, y).
*
* @param x the X coordinate of the end of the new line
* @param y the Y coordinate of the end of the new line
*/
void line_to(double x, double y);
/** Adds a cubic Bezier spline to the path from the current point to position
* (x3, y3) in user-space coordinates, using (x1, y1) and (x2, y2) as the
* control points. After this call the current point will be (x3, y3).
*
* If there is no current point before the call to curve_to()
* this function will behave as if preceded by a call to
* move_to(x1, y1).
*
* @param x1 the X coordinate of the first control point
* @param y1 the Y coordinate of the first control point
* @param x2 the X coordinate of the second control point
* @param y2 the Y coordinate of the second control point
* @param x3 the X coordinate of the end of the curve
* @param y3 the Y coordinate of the end of the curve
*/
void curve_to(double x1, double y1, double x2, double y2, double x3, double y3);
/** Adds a circular arc of the given radius to the current path. The arc is
* centered at (@a xc, @a yc), begins at @a angle1 and proceeds in the direction of
* increasing angles to end at @a angle2. If @a angle2 is less than @a angle1 it will
* be progressively increased by 2*M_PI until it is greater than @a angle1.
*
* If there is a current point, an initial line segment will be added to the
* path to connect the current point to the beginning of the arc. If this
* initial line is undesired, it can be avoided by calling
* begin_new_sub_path() before calling arc().
*
* Angles are measured in radians. An angle of 0 is in the direction of the
* positive X axis (in user-space). An angle of M_PI/2.0 radians (90 degrees) is
* in the direction of the positive Y axis (in user-space). Angles increase
* in the direction from the positive X axis toward the positive Y axis. So
* with the default transformation matrix, angles increase in a clockwise
* direction.
*
* ( To convert from degrees to radians, use degrees * (M_PI / 180.0). )
*
* This function gives the arc in the direction of increasing angles; see
* arc_negative() to get the arc in the direction of decreasing angles.
*
* The arc is circular in user-space. To achieve an elliptical arc, you can
* scale the current transformation matrix by different amounts in the X and
* Y directions. For example, to draw an ellipse in the box given by x, y,
* width, height:
*
* @code
* context->save();
* context->translate(x, y);
* context->scale(width / 2.0, height / 2.0);
* context->arc(0.0, 0.0, 1.0, 0.0, 2 * M_PI);
* context->restore();
* @endcode
*
* @param xc X position of the center of the arc
* @param yc Y position of the center of the arc
* @param radius the radius of the arc
* @param angle1 the start angle, in radians
* @param angle2 the end angle, in radians
*/
void arc(double xc, double yc, double radius, double angle1, double angle2);
/** Adds a circular arc of the given @a radius to the current path. The arc is
* centered at (@a xc, @a yc), begins at @a angle1 and proceeds in the direction of
* decreasing angles to end at @a angle2. If @a angle2 is greater than @a angle1 it
* will be progressively decreased by 2*M_PI until it is greater than @a angle1.
*
* See arc() for more details. This function differs only in the direction of
* the arc between the two angles.
*
* @param xc X position of the center of the arc
* @param yc Y position of the center of the arc
* @param radius the radius of the arc
* @param angle1 the start angle, in radians
* @param angle2 the end angle, in radians
*/
void arc_negative(double xc, double yc, double radius, double angle1, double angle2);
/** If the current subpath is not empty, begin a new subpath. After this call
* the current point will offset by (x, y).
*
* Given a current point of (x, y),
* @code
* rel_move_to(dx, dy)
* @endcode
* is logically equivalent to
* @code
* move_to(x + dx, y + dy)
* @endcode
*
* @param dx the X offset
* @param dy the Y offset
*
* It is an error to call this function with no current point. Doing
* so will cause this to shutdown with a status of
* CAIRO_STATUS_NO_CURRENT_POINT. Cairomm will then throw an exception.
*/
void rel_move_to(double dx, double dy);
/** Relative-coordinate version of line_to(). Adds a line to the path from
* the current point to a point that is offset from the current point by (dx,
* dy) in user space. After this call the current point will be offset by
* (dx, dy).
*
* Given a current point of (x, y),
* @code
* rel_line_to(dx, dy)
* @endcode
* is logically equivalent to
* @code
* line_to(x + dx, y + dy).
* @endcode
*
* @param dx the X offset to the end of the new line
* @param dy the Y offset to the end of the new line
*
* It is an error to call this function with no current point. Doing
* so will cause this to shutdown with a status of
* CAIRO_STATUS_NO_CURRENT_POINT. Cairomm will then throw an exception.
*/
void rel_line_to(double dx, double dy);
/** Relative-coordinate version of curve_to(). All offsets are relative to
* the current point. Adds a cubic Bezier spline to the path from the current
* point to a point offset from the current point by (dx3, dy3), using points
* offset by (dx1, dy1) and (dx2, dy2) as the control points. After this
* call the current point will be offset by (dx3, dy3).
*
* Given a current point of (x, y),
* @code
* rel_curve_to(dx1, dy1, dx2, dy2, dx3, dy3)
* @endcode
* is logically equivalent to
* @code
* curve_to(x + dx1, y + dy1, x + dx2, y + dy2, x + dx3, y + dy3).
* @endcode
*
* @param dx1 the X offset to the first control point
* @param dy1 the Y offset to the first control point
* @param dx2 the X offset to the second control point
* @param dy2 the Y offset to the second control point
* @param dx3 the X offset to the end of the curve
* @param dy3 the Y offset to the end of the curve
*
* It is an error to call this function with no current point. Doing
* so will cause this to shutdown with a status of
* CAIRO_STATUS_NO_CURRENT_POINT. Cairomm will then throw an exception.
*/
void rel_curve_to(double dx1, double dy1, double dx2, double dy2, double dx3, double dy3);
/** Adds a closed-subpath rectangle of the given size to the current path at
* position (x, y) in user-space coordinates.
*
* This function is logically equivalent to:
*
* @code
* context->move_to(x, y);
* context->rel_line_to(width, 0);
* context->rel_line_to(0, height);
* context->rel_line_to(-width, 0);
* context->close_path();
* @endcode
*
* @param x the X coordinate of the top left corner of the rectangle
* @param y the Y coordinate to the top left corner of the rectangle
* @param width the width of the rectangle
* @param height the height of the rectangle
*/
void rectangle(double x, double y, double width, double height);
/** Adds a line segment to the path from the current point to the beginning
* of the current subpath, (the most recent point passed to move_to()), and
* closes this subpath. After this call the current point will be at the
* joined endpoint of the sub-path.
*
* The behavior of close_path() is distinct from simply calling line_to()
* with the equivalent coordinate in the case of stroking. When a closed
* subpath is stroked, there are no caps on the ends of the subpath. Instead,
* there is a line join connecting the final and initial segments of the
* subpath.
*
* If there is no current point before the call to close_path(),
* this function will have no effect.
*
*/
void close_path();
/** A drawing operator that paints the current source everywhere within the
* current clip region.
*/
void paint();
/** A drawing operator that paints the current source everywhere within the
* current clip region using a mask of constant alpha value alpha. The effect
* is similar to paint(), but the drawing is faded out using the alpha
* value.
*
* @param alpha an alpha value, between 0 (transparent) and 1 (opaque)
*/
void paint_with_alpha(double alpha);
/** A drawing operator that paints the current source using the alpha channel
* of pattern as a mask. (Opaque areas of mask are painted with the source,
* transparent areas are not painted.)
*
* @param pattern a Pattern
*/
void mask(const RefPtr<const Pattern>& pattern);
/** A drawing operator that paints the current source using the alpha channel
* of surface as a mask. (Opaque areas of surface are painted with the
* source, transparent areas are not painted.)
*
* @param surface a Surface
* @param surface_x X coordinate at which to place the origin of surface
* @param surface_y Y coordinate at which to place the origin of surface
*/
void mask(const RefPtr<const Surface>& surface, double surface_x, double surface_y);
/** A drawing operator that strokes the current Path according to the current
* line width, line join, line cap, and dash settings. After stroke(),
* the current Path will be cleared from the cairo Context.
*
* @sa set_line_width()
* @sa set_line_join()
* @sa set_line_cap()
* @sa set_dash()
* @sa stroke_preserve().
*
* Note: Degenerate segments and sub-paths are treated specially and
* provide a useful result. These can result in two different
* situations:
*
* 1. Zero-length "on" segments set in set_dash(). If the cap style is
* Cairo::LINE_CAP_ROUND or Cairo::LINE_CAP_SQUARE then these segments will
* be drawn as circular dots or squares respectively. In the case of
* Cairo::LINE_CAP_SQUARE, the orientation of the squares is determined by
* the direction of the underlying path.
*
* 2. A sub-path created by move_to() followed by either a close_path() or
* one or more calls to line_to() to the same coordinate as the move_to(). If
* the cap style is Cairo::LINE_CAP_ROUND then these sub-paths will be drawn
* as circular dots. Note that in the case of Cairo::LINE_CAP_SQUARE a
* degenerate sub-path will not be drawn at all, (since the correct
* orientation is indeterminate).
*
* In no case will a cap style of Cairo::LINE_CAP_BUTT cause anything to be
* drawn in the case of either degenerate segments or sub-paths.
*/
void stroke();
/** A drawing operator that strokes the current Path according to the current
* line width, line join, line cap, and dash settings. Unlike stroke(),
* stroke_preserve() preserves the Path within the cairo Context.
*
* @sa set_line_width()
* @sa set_line_join()
* @sa set_line_cap()
* @sa set_dash()
* @sa stroke_preserve().
*/
void stroke_preserve();
/** A drawing operator that fills the current path according to the current
* fill rule, (each sub-path is implicitly closed before being filled). After
* fill(), the current path will be cleared from the cairo context.
*
* @sa set_fill_rule()
* @sa fill_preserve()
*/
void fill();
/** A drawing operator that fills the current path according to the current
* fill rule, (each sub-path is implicitly closed before being filled).
* Unlike fill(), fill_preserve() preserves the path within the
* cairo Context.
*
* @sa set_fill_rule()
* @sa fill().
*/
void fill_preserve();
/**
* Emits the current page for backends that support multiple pages, but
* doesn't clear it, so, the contents of the current page will be retained
* for the next page too. Use show_page() if you want to get an
* empty page after the emission.
*
* This is a convenience function that simply calls Surface::copy_page() on
* @a cr's target.
*/
void copy_page();
/**
* Emits and clears the current page for backends that support multiple
* pages. Use copy_page() if you don't want to clear the page.
*
* This is a convenience function that simply calls
* Surface::show_page() on @a cr's target.
*/
void show_page();
/**
* Tests whether the given point is inside the area that would be
* affected by a stroke() operation given the current path and
* stroking parameters. Surface dimensions and clipping are not taken
* into account.
*
* @param x X coordinate of the point to test
* @param y Y coordinate of the point to test
* @returns A non-zero value if the point is inside, or zero if outside.
*
* @sa stroke()
* @sa set_line_width()
* @sa set_line_join()
* @sa set_line_cap()
* @sa set_dash()
* @sa stroke_preserve().
*
*/
bool in_stroke(double x, double y) const;
/**
* Tests whether the given point is inside the area that would be
* affected by a fill() operation given the current path and
* filling parameters. Surface dimensions and clipping are not taken
* into account.
*
* @param x X coordinate of the point to test
* @param y Y coordinate of the point to test
* @returns A non-zero value if the point is inside, or zero if outside.
*
* @sa fill()
* @sa set_fill_rule()
* @sa fill_preserve()
*/
bool in_fill(double x, double y) const;
/**
* Tests whether the given point is inside the area that would be visible
* through the current clip, i.e. the area that would be filled by a paint()
* operation.
*
* Return value: A non-zero value if the point is inside, or zero if outside.
*
* @param x X coordinate of the point to test
* @param y Y coordinate of the point to test
*
* @sa clip()
* @sa clip_preserve()
*
* @since 1.10
*/
bool in_clip(double x, double y) const;
/**
* Computes a bounding box in user coordinates covering the area that would
* be affected, (the "inked" area), by a stroke() operation given the current
* path and stroke parameters. If the current path is empty, returns an empty
* rectangle ((0,0), (0,0)). Surface dimensions and clipping are not taken
* into account.
*
* Note that if the line width is set to exactly zero, then stroke_extents()
* will return an empty rectangle. Contrast with path_extents() which can be
* used to compute the non-empty bounds as the line width approaches zero.
*
* Note that stroke_extents() must necessarily do more work to compute the
* precise inked areas in light of the stroke parameters, so path_extents()
* may be more desirable for sake of performance if non-inked path extents
* are desired.
*
* @param x1 left of the resulting extents
* @param y1 top of the resulting extents
* @param x2 right of the resulting extents
* @param y2 bottom of the resulting extents
*
* @sa stroke()
* @sa set_line_width()
* @sa set_line_join()
* @sa set_line_cap()
* @sa set_dash()
* @sa stroke_preserve()
*/
void get_stroke_extents(double& x1, double& y1, double& x2, double& y2) const;
/**
* Computes a bounding box in user coordinates covering the area that would
* be affected, (the "inked" area), by a fill() operation given the current
* path and fill parameters. If the current path is empty, returns an empty
* rectangle ((0,0), (0,0)). Surface dimensions and clipping are not taken
* into account.
*
* Contrast with path_extents(), which is similar, but returns non-zero
* extents for some paths with no inked area, (such as a simple line
* segment).
*
* Note that fill_extents() must necessarily do more work to compute the
* precise inked areas in light of the fill rule, so path_extents() may be
* more desirable for sake of performance if the non-inked path extents are
* desired.
*
* @param x1 left of the resulting extents
* @param y1 top of the resulting extents
* @param x2 right of the resulting extents
* @param y2 bottom of the resulting extents
*
* @sa fill()
* @sa set_fill_rule()
* @sa full_preserve()
*/
void get_fill_extents(double& x1, double& y1, double& x2, double& y2) const;
/** Reset the current clip region to its original, unrestricted state. That
* is, set the clip region to an infinitely large shape containing the target
* surface. Equivalently, if infinity is too hard to grasp, one can imagine
* the clip region being reset to the exact bounds of the target surface.
*
* Note that code meant to be reusable should not call reset_clip() as it
* will cause results unexpected by higher-level code which calls clip().
* Consider using save() and restore() around clip() as a more robust means
* of temporarily restricting the clip region.
*/
void reset_clip();
/** Establishes a new clip region by intersecting the current clip region
* with the current Path as it would be filled by fill() and according to the
* current fill rule.
*
* After clip(), the current path will be cleared from the cairo Context.
*
* The current clip region affects all drawing operations by effectively
* masking out any changes to the surface that are outside the current clip
* region.
*
* Calling clip() can only make the clip region smaller, never larger. But
* the current clip is part of the graphics state, so a temporary restriction
* of the clip region can be achieved by calling clip() within a
* save()/restore() pair. The only other means of increasing the size of the
* clip region is reset_clip().
*
* @sa set_fill_rule()
*/
void clip();
/** Establishes a new clip region by intersecting the current clip region
* with the current path as it would be filled by fill() and according to the
* current fill rule.
*
* Unlike clip(), clip_preserve preserves the path within the cairo
* Context.
*
* @sa clip()
* @sa set_fill_rule()
*/
void clip_preserve();
/**
* Computes a bounding box in user coordinates covering the area inside the
* current clip.
*
* @param x1 left of the resulting extents
* @param y1 top of the resulting extents
* @param x2 right of the resulting extents
* @param y2 bottom of the resulting extents
*
* @since 1.4
**/
void get_clip_extents(double& x1, double& y1, double& x2, double& y2) const;
/**
* Returns the current clip region as a list of rectangles in user coordinates.
*
* This function will throw an exception if the clip region cannot be
* represented as a list of user-space rectangles.
*
* @param rectangles a vector to store the rectangles into
*
* @exception
*
* @since 1.4
*/
void copy_clip_rectangle_list(std::vector<Rectangle>& rectangles) const;
/**
* Selects a family and style of font from a simplified description as a
* family name, slant and weight. Cairo provides no operation to list
* available family names on the system (this is a "toy", remember), but the
* standard CSS2 generic family names, ("serif", "sans-serif", "cursive",
* "fantasy", "monospace"), are likely to work as expected.
*
* Note: The select_font_face() function call is part of what the cairo
* designers call the "toy" text API. It is convenient for short demos and
* simple programs, but it is not expected to be adequate for serious
* text-using applications.
*
* If @a family starts with the string "@cairo:", or if no native font
* backends are compiled in, cairo will use an internal font family. The
* internal font family recognizes many modifiers in the @family string, most
* notably, it recognizes the string "monospace". That is, the family name
* "@cairo:monospace" will use the monospace version of the internal font
* family.
*
* For "real" font selection, see the font-backend-specific
* Cairo::FontFace::create functions for the font backend you are using. (For
* example, if you are using the freetype-based cairo-ft font backend, see
* Cairo::FtFontFace::create().) The resulting font face could then be used
* with Cairo::ScaledFont::create() and set_scaled_font().
*
* Similarly, when using the "real" font support, you can call directly into
* the underlying font system, (such as fontconfig or freetype), for
* operations such as listing available fonts, etc.
*
* It is expected that most applications will need to use a more
* comprehensive font handling and text layout library, (for example, pango),
* in conjunction with cairo.
*
* If text is drawn without a call to select_font_face(), (nor
* set_font_face() nor set_scaled_font()), the default family is
* platform-specific, but is essentially "sans-serif". Default slant is
* Cairo::FONT_SLANT_NORMAL, and default weight is Cairo::FONT_WEIGHT_NORMAL.
*
* This function is equivalent to a call to Cairo::ToyFontFace::create()
* followed by set_font_face().
*
* @param family a font family name, encoded in UTF-8
* @param slant the slant for the font
* @param weight the weight for the font
*
**/
void select_font_face(const std::string& family, FontSlant slant, FontWeight weight);
/**
* Sets the current font matrix to a scale by a factor of @a size, replacing
* any font matrix previously set with set_font_size() or set_font_matrix().
* This results in a font size of @a size user space units. (More precisely,
* this matrix will result in the font's em-square being a @size by @a size
* square in user space.)
*
* If text is drawn without a call to set_font_size(), (nor set_font_matrix()
* nor set_scaled_font()), the default font size is 10.0.
*
* @param size the new font size, in user space units)
*/
void set_font_size(double size);
/**
* Sets the current font matrix to @matrix. The font matrix gives a
* transformation from the design space of the font (in this space, the
* em-square is 1 unit by 1 unit) to user space. Normally, a simple scale is
* used (see set_font_size()), but a more complex font matrix can be used to
* shear the font or stretch it unequally along the two axes
*
* @param matrix a Cairo::Matrix describing a transform to be applied to the
* current font.
*/
void set_font_matrix(const Matrix& matrix);
/**
* Returns the current font matrix
*
* @param matrix a Cairo::Matrix to store the results into (in/out parameter)
* @sa set_font_matrix()
*/
void get_font_matrix(Matrix& matrix) const;
/**
* Sets a set of custom font rendering options. Rendering options are derived
* by merging these options with the options derived from underlying surface;
* if the value in @a options has a default value (like
* Cairo::ANTIALIAS_DEFAULT), then the value from the surface is used.
*
* @param options font options to use
*/
void set_font_options(const FontOptions& options);
/* To keep 1.6.x ABI */
void set_font_matrix(const cairo_matrix_t& matrix);
void get_font_matrix(cairo_matrix_t& matrix) const;
/**
* Retrieves font rendering options set via set_font_options(). Note that the
* returned options do not include any options derived from the underlying
* surface; they are literally the options passed to set_font_options().
*
* @param options a FontOptions object into which to store the retrieved
* options. All existing values are overwritten
* @since 1.8
*/
void get_font_options(FontOptions& options) const;
/**
* Replaces the current font face, font matrix, and font options in the
* context with those of the @a scaled_font. Except for some translation, the
* current CTM of the context should be the same as that of the
* #cairo_scaled_font_t, which can be accessed using
* Cairo::ScaledFont::get_ctm().
*
* @param scaled_font a scaled font
* @since 1.8
*/
void set_scaled_font(const RefPtr<const ScaledFont>& scaled_font);
/** Gets the current scaled font.
*
* @since 1.8
**/
RefPtr<ScaledFont> get_scaled_font();
/**
* A drawing operator that generates the shape from a string of UTF-8
* characters, rendered according to the current font_face, font_size
* (font_matrix), and font_options.
*
* This function first computes a set of glyphs for the string of text. The
* first glyph is placed so that its origin is at the current point. The
* origin of each subsequent glyph is offset from that of the previous glyph
* by the advance values of the previous glyph.
*
* After this call the current point is moved to the origin of where the
* next glyph would be placed in this same progression. That is, the current
* point will be at the origin of the final glyph offset by its advance
* values. This allows for easy display of a single logical string with
* multiple calls to show_text().
*
* Note: The show_text() function call is part of what the cairo
* designers call the "toy" text API. It is convenient for short demos and
* simple programs, but it is not expected to be adequate for serious
* text-using applications. See show_glyphs() for the "real" text
* display API in cairo.
*
* @param utf8 a string containing text encoded in UTF-8
*/
void show_text(const std::string& utf8);
/**
* A drawing operator that generates the shape from an array of glyphs,
* rendered according to the current font face, font size (font matrix), and
* font options.
*
* @param glyphs vector of glyphs to show
* @param num_glyphs number of glyphs to show
**/
void show_glyphs(const std::vector<Glyph>& glyphs);
/**
* This operation has rendering effects similar to show_glyphs() but, if the
* target surface supports it, uses the provided text and cluster mapping to
* embed the text for the glyphs shown in the output. If the target does not
* support the extended attributes, this function acts like the basic
* show_glyphs() as if it had been passed @a glyphs and @a num_glyphs.
*
* The mapping between @a utf8 and @a glyphs is provided by an array of
* <firstterm>clusters</firstterm>. Each cluster covers a number of text
* bytes and glyphs, and neighboring clusters cover neighboring areas of @a
* utf8 and @a glyphs. The clusters should collectively cover @a utf8 and @a
* glyphs in entirety.
*
* The first cluster always covers bytes from the beginning of @a utf8. If @a
* cluster_flags do not have the Cairo::TEXT_CLUSTER_FLAG_BACKWARD set, the
* first cluster also covers the beginning of @a glyphs, otherwise it covers
* the end of the @a glyphs array and following clusters move backward.
*
* See Cairo::TextCluster for constraints on valid clusters.
*
* @param utf8: a string of text encoded in UTF-8
* @param glyphs: vector of glyphs to show
* @param clusters: vector of cluster mapping information
* @param cluster_flags: cluster mapping flags
*
* @since 1.8
**/
void show_text_glyphs(const std::string& utf8,
const std::vector<Glyph>& glyphs,
const std::vector<TextCluster>& clusters,
TextClusterFlags cluster_flags);
/// @{
/** Gets the current font face
**/
RefPtr<FontFace> get_font_face();
RefPtr<const FontFace> get_font_face() const;
/// @}
/**
* Gets the font extents for the currently selected font.
*
* @param extents a Cairo::FontExtents object
*/
void get_font_extents(FontExtents& extents) const;
/**
* Replaces the current font face in the context with @a font_face
* @a font_face. The replaced font face in the context will be destroyed if
* there are no other references to it.
*
* @param font_face a font face
*/
//FIXME: C API acceps NULL to restore the default font. Does C++ API support that?
void set_font_face(const RefPtr<const FontFace>& font_face);
/**
* Gets the extents for a string of text. The extents describe a user-space
* rectangle that encloses the "inked" portion of the text, (as it would be
* drawn by show_text()). Additionally, the x_advance and y_advance values
* indicate the amount by which the current point would be advanced by
* show_text().
*
* Note that whitespace characters do not directly contribute to the size of
* the rectangle (extents.width and extents.height). They do contribute
* indirectly by changing the position of non-whitespace characters. In
* particular, trailing whitespace characters are likely to not affect the
* size of the rectangle, though they will affect the x_advance and y_advance
* values.
*
* @param utf8 a string of text encoded in UTF-8
* @param extents a TextExtents object
*/
void get_text_extents(const std::string& utf8, TextExtents& extents) const;
/**
* Gets the extents for an array of glyphs. The extents describe a user-space
* rectangle that encloses the "inked" portion of the glyphs, (as they would
* be drawn by show_glyphs()). Additionally, the x_advance and y_advance
* values indicate the amount by which the current point would be advanced by
* show_glyphs().
*
* Note that whitespace glyphs do not contribute to the size of the rectangle
* (extents.width and extents.height).
*
* @param glyphs a vector of glyphs
* @param extents a TextExtents object
*/
void get_glyph_extents(const std::vector<Glyph>& glyphs, TextExtents& extents) const;
/**
* Adds closed paths for text to the current path. The generated path if
* filled, achieves an effect similar to that of show_text().
*
* Text conversion and positioning is done similar to show_text().
*
* Like show_text(), After this call the current point is moved to the origin
* of where the next glyph would be placed in this same progression. That is,
* the current point will be at the origin of the final glyph offset by its
* advance values. This allows for chaining multiple calls to to text_path()
* without having to set current point in between.
*
* Note: The text_path() function call is part of what the cairo designers
* call the "toy" text API. It is convenient for short demos and simple
* programs, but it is not expected to be adequate for serious text-using
* applications. See glyph_path() for the "real" text path API in cairo.
*
* @param utf8 a string of text encoded in UTF-8
*/
void text_path(const std::string& utf8);
/** Adds closed paths for the glyphs to the current path. The generated path
* if filled, achieves an effect similar to that of show_glyphs().
*
* @param glyphs a vector of glyphs
*/
void glyph_path(const std::vector<Glyph>& glyphs);
/** Gets the current compositing operator for a cairo Context
*/
Operator get_operator() const;
/// @{
/** Gets the current source pattern for the Context
*/
RefPtr<Pattern> get_source();
RefPtr<const Pattern> get_source() const;
/// @}
/** Gets the current tolerance value, as set by set_tolerance()
*/
double get_tolerance() const;
/** Gets the current shape antialiasing mode, as set by set_antialias()
*/
Antialias get_antialias() const;
/** Gets the current point of the current path, which is conceptually the
* final point reached by the path so far.
*
* The current point is returned in the user-space coordinate system. If
* there is no defined current point then x and y will both be set to 0.0. It
* is possible to check this in advance with has_current_point().
*
* Most path construction functions alter the current point. See the
* following for details on how they affect the current point: clear_path(),
* move_to(), line_to(), curve_to(), arc(), rel_move_to(), rel_line_to(),
* rel_curve_to(), arc(), and text_path()
*
* Some functions use and alter the current point but do not otherwise change
* current path: show_text().
*
* Some functions unset the current path and as a result, current point:
* fill(), stroke().
*
* @param x return value for X coordinate of the current point
* @param y return value for Y coordinate of the current point
*
* @sa has_current_point()
*/
void get_current_point (double& x, double& y) const;
/**
* Checks if there is a current point defined. See get_current_point() for
* details on the current point.
*
* @returns @c true if a current point is defined.
*
* @since 1.6
*/
bool has_current_point() const;
/** Gets the current fill rule, as set by set_fill_rule().
*/
FillRule get_fill_rule() const;
/**
* Gets the current line width, as set by set_line_width(). Note that the
* value is unchanged even if the CTM has changed between the calls to
* set_line_width() and get_line_width().
*/
double get_line_width() const;
/** Gets the current line cap style, as set by set_line_cap()
*/
LineCap get_line_cap() const;
/** Gets the current line join style, as set by set_line_join()
*/
LineJoin get_line_join() const;
/** Gets the current miter limit, as set by set_miter_limit()
*/
double get_miter_limit() const;
/**
* Gets the current dash array and offset.
*
* @param dashes return value for the dash array.
* @param offset return value for the current dash offset.
*
* @since 1.4
**/
void get_dash(std::vector<double>& dashes, double& offset) const;
/** Stores the current transformation matrix (CTM) into matrix.
*
* @param matrix return value for the matrix
*/
void get_matrix(Matrix& matrix);
/* To keep 1.6.x ABI */
void get_matrix(cairo_matrix_t& matrix);
/**
* Returns the current transformation matrix (CTM)
* @since 1.8
*/
Matrix get_matrix() const;
/// @{
/** Gets the target surface associated with this Context.
*
* @exception
*/
RefPtr<Surface> get_target();
RefPtr<const Surface> get_target() const;
/// @}
//TODO: Copy or reference-count a Path somethow instead of asking the caller to delete it?
/** Creates a copy of the current path and returns it to the user.
*
* @todo See cairo_path_data_t for hints on how to iterate over the returned
* data structure.
*
* @note The caller owns the Path object returned from this function. The
* Path object must be freed when you are finished with it.
*/
Path* copy_path() const;
/**
* Computes a bounding box in user-space coordinates covering the points on
* the current path. If the current path is empty, returns an empty rectangle
* ((0,0), (0,0)). Stroke parameters, fill rule, surface dimensions and
* clipping are not taken into account.
*
* Contrast with fill_extents() and stroke_extents() which return the extents
* of only the area that would be "inked" by the corresponding drawing
* operations.
*
* The result of path_extents() is defined as equivalent to the limit of
* stroke_extents() with LINE_CAP_ROUND as the line width approaches 0.0, (but
* never reaching the empty-rectangle returned by stroke_extents() for a line
* width of 0.0).
*
* Specifically, this means that zero-area sub-paths such as
* move_to();line_to() segments, (even degenerate cases where the coordinates
* to both calls are identical), will be considered as contributing to the
* extents. However, a lone move_to() will not contribute to the results of
* path_extents().
*
* @param x1 left of the resulting extents
* @param y1 top of the resulting extents
* @param x2 right of the resulting extents
* @param y2 bottom of the resulting extents
*
* @since 1.6
*/
void get_path_extents(double& x1, double& y1, double& x2, double& y2) const;
/** Gets a flattened copy of the current path and returns it to the user
*
* @todo See cairo_path_data_t for hints on how to iterate over the returned
* data structure.
*
* This function is like copy_path() except that any curves in the path will
* be approximated with piecewise-linear approximations, (accurate to within
* the current tolerance value). That is, the result is guaranteed to not have
* any elements of type CAIRO_PATH_CURVE_TO which will instead be
* replaced by a series of CAIRO_PATH_LINE_TO elements.
*
* @note The caller owns the Path object returned from this function. The
* Path object must be freed when you are finished with it.
*/
Path* copy_path_flat() const;
/** Append the path onto the current path. The path may be either the return
* value from one of copy_path() or copy_path_flat() or it may be constructed
* manually.
*
* @param path path to be appended
*/
void append_path(const Path& path);
/** Temporarily redirects drawing to an intermediate surface known as a group.
* The redirection lasts until the group is completed by a call to pop_group()
* or pop_group_to_source(). These calls provide the result of any drawing to
* the group as a pattern, (either as an explicit object, or set as the source
* pattern).
*
* This group functionality can be convenient for performing intermediate
* compositing. One common use of a group is to render objects as opaque
* within the group, (so that they occlude each other), and then blend the
* result with translucence onto the destination.
*
* Groups can be nested arbitrarily deep by making balanced calls to
* push_group()/pop_group(). Each call pushes/pops the new target group
* onto/from a stack.
*
* The push_group() function calls save() so that any changes to the graphics
* state will not be visible outside the group, (the pop_group functions call
* restore()).
*
* By default the intermediate group will have a content type of
* CONTENT_COLOR_ALPHA. Other content types can be chosen for the group by
* using push_group_with_content() instead.
*
* As an example, here is how one might fill and stroke a path with
* translucence, but without any portion of the fill being visible under the
* stroke:
*
* @code
* cr->push_group();
* cr->set_source(fill_pattern);
* cr->fill_preserve();
* cr->set_source(stroke_pattern);
* cr->stroke();
* cr->pop_group_to_source();
* cr->paint_with_alpha(alpha);
* @endcode
*
* @since 1.2
*/
void push_group();
/**
* Temporarily redirects drawing to an intermediate surface known as a
* group. The redirection lasts until the group is completed by a call
* to pop_group() or pop_group_to_source(). These calls provide the result of
* any drawing to the group as a pattern, (either as an explicit object, or set
* as the source pattern).
*
* The group will have a content type of @content. The ability to control this
* content type is the only distinction between this function and push_group()
* which you should see for a more detailed description of group rendering.
*
* @param content indicates the type of group that will be created
*
* @since 1.2
*/
void push_group_with_content(Content content);
/**
* Terminates the redirection begun by a call to push_group() or
* push_group_with_content() and returns a new pattern containing the results
* of all drawing operations performed to the group.
*
* The pop_group() function calls restore(), (balancing a call to save() by
* the push_group function), so that any changes to the graphics state will
* not be visible outside the group.
*
* @return a (surface) pattern containing the results of all drawing
* operations performed to the group.
*
* @since 1.2
**/
RefPtr<Pattern> pop_group();
/**
* Terminates the redirection begun by a call to push_group() or
* push_group_with_content() and installs the resulting pattern as the source
* pattern in the given cairo Context.
*
* The behavior of this function is equivalent to the sequence of operations:
*
* @code
* RefPtr<Pattern> group = cr->pop_group();
* cr->set_source(group);
* @endcode
*
* but is more convenient as their is no need for a variable to store
* the short-lived pointer to the pattern.
*
* The pop_group() function calls restore(), (balancing a call to save() by
* the push_group function), so that any changes to the graphics state will
* not be visible outside the group.
*
* @since 1.2
**/
void pop_group_to_source();
/**
* Gets the target surface for the current group as started by the most recent
* call to push_group() or push_group_with_content().
*
* This function will return NULL if called "outside" of any group rendering
* blocks, (that is, after the last balancing call to pop_group() or
* pop_group_to_source()).
*
* @exception
*
* @since 1.2
**/
RefPtr<Surface> get_group_target();
/** Same as the non-const version but returns a reference to a const Surface
*
* @since 1.2
*/
RefPtr<const Surface> get_group_target() const;
/** The base cairo C type that is wrapped by Cairo::Context
*/
typedef cairo_t cobject;
/** Gets a pointer to the base C type that is wrapped by the Context
*/
inline cobject* cobj() { return m_cobject; }
/** Gets a pointer to the base C type that is wrapped by the Context
*/
inline const cobject* cobj() const { return m_cobject; }
#ifndef DOXYGEN_IGNORE_THIS
///For use only by the cairomm implementation.
inline ErrorStatus get_status() const
{ return cairo_status(const_cast<cairo_t*>(cobj())); }
void reference() const;
void unreference() const;
#endif //DOXYGEN_IGNORE_THIS
protected:
cobject* m_cobject;
};
} // namespace Cairo
#endif //__CAIROMM_CONTEXT_H
// vim: ts=2 sw=2 et