/* GdkPixbuf library - Scaling and compositing functions * * Copyright (C) 1999 The Free Software Foundation * * Author: Owen Taylor * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, see . */ #include "config.h" #include #include #include "gdk-pixbuf-transform.h" #include "gdk-pixbuf-private.h" #include "pixops/pixops.h" /** * SECTION:scaling * @Short_description: Scaling pixbufs and scaling and alpha blending pixbufs * @Title: Scaling * @See_also: GdkRGB. * * The GdkPixBuf contains functions to scale pixbufs, to scale * pixbufs and alpha blend against an existing image, and to scale * pixbufs and alpha blend against a solid color or checkerboard. * Alpha blending a checkerboard is a common way to show an image with * an alpha channel in image-viewing and editing software. * * Note that in these functions, the terms ‘alpha blending’ and ‘compositing’ * are used synonymously. * * Since the full-featured functions (gdk_pixbuf_scale(), * gdk_pixbuf_composite(), and gdk_pixbuf_composite_color()) are * rather complex to use and have many arguments, two simple * convenience functions are provided, gdk_pixbuf_scale_simple() and * gdk_pixbuf_composite_color_simple() which create a new pixbuf of a * given size, scale an original image to fit, and then return the * new pixbuf. * * If the destination pixbuf was created from a readonly source, these * operations will force a copy into a mutable buffer. * * Scaling and alpha blending functions take advantage of MMX hardware * acceleration on systems where MMX is supported. If gdk-pixbuf is built * with the Sun mediaLib library, these functions are instead accelerated * using mediaLib, which provides hardware acceleration on Intel, AMD, * and Sparc chipsets. If desired, mediaLib support can be turned off by * setting the `GDK_DISABLE_MEDIALIB` environment variable. * * The alpha blending function used is: * |[ * Cd = Cs·As + Cd(1-As) * ]| * where `Cd` is the destination pixel color, `Cs` is the source pixel color, * and `As` is the source pixel alpha. * * The following example demonstrates handling an expose event by * rendering the appropriate area of a source image (which is scaled * to fit the widget) onto the widget's window. The source image is * rendered against a checkerboard, which provides a visual * representation of the alpha channel if the image has one. If the * image doesn't have an alpha channel, calling * gdk_pixbuf_composite_color() function has exactly the same effect * as calling gdk_pixbuf_scale(). * * ## Handling an expose event * * |[ * gboolean * expose_cb (GtkWidget *widget, GdkEventExpose *event, gpointer data) * { * GdkPixbuf *dest; * * dest = gdk_pixbuf_new (GDK_COLORSPACE_RGB, FALSE, 8, event->area.width, event->area.height); * * gdk_pixbuf_composite_color (pixbuf, dest, * 0, 0, event->area.width, event->area.height, * -event->area.x, -event->area.y, * (double) widget->allocation.width / gdk_pixbuf_get_width (pixbuf), * (double) widget->allocation.height / gdk_pixbuf_get_height (pixbuf), * GDK_INTERP_BILINEAR, 255, * event->area.x, event->area.y, 16, 0xaaaaaa, 0x555555); * * gdk_draw_pixbuf (widget->window, widget->style->fg_gc[GTK_STATE_NORMAL], dest, * 0, 0, event->area.x, event->area.y, * event->area.width, event->area.height, * GDK_RGB_DITHER_NORMAL, event->area.x, event->area.y); * * gdk_pixbuf_unref (dest); * * return TRUE; * } * ]| */ /** * gdk_pixbuf_scale: * @src: a #GdkPixbuf * @dest: the #GdkPixbuf into which to render the results * @dest_x: the left coordinate for region to render * @dest_y: the top coordinate for region to render * @dest_width: the width of the region to render * @dest_height: the height of the region to render * @offset_x: the offset in the X direction (currently rounded to an integer) * @offset_y: the offset in the Y direction (currently rounded to an integer) * @scale_x: the scale factor in the X direction * @scale_y: the scale factor in the Y direction * @interp_type: the interpolation type for the transformation. * * Creates a transformation of the source image @src by scaling by * @scale_x and @scale_y then translating by @offset_x and @offset_y, * then renders the rectangle (@dest_x, @dest_y, @dest_width, * @dest_height) of the resulting image onto the destination image * replacing the previous contents. * * Try to use gdk_pixbuf_scale_simple() first, this function is * the industrial-strength power tool you can fall back to if * gdk_pixbuf_scale_simple() isn't powerful enough. * * If the source rectangle overlaps the destination rectangle on the * same pixbuf, it will be overwritten during the scaling which * results in rendering artifacts. **/ void gdk_pixbuf_scale (const GdkPixbuf *src, GdkPixbuf *dest, int dest_x, int dest_y, int dest_width, int dest_height, double offset_x, double offset_y, double scale_x, double scale_y, GdkInterpType interp_type) { const guint8 *src_pixels; guint8 *dest_pixels; g_return_if_fail (GDK_IS_PIXBUF (src)); g_return_if_fail (GDK_IS_PIXBUF (dest)); g_return_if_fail (dest_x >= 0 && dest_x + dest_width <= dest->width); g_return_if_fail (dest_y >= 0 && dest_y + dest_height <= dest->height); offset_x = floor (offset_x + 0.5); offset_y = floor (offset_y + 0.5); /* Force an implicit copy */ dest_pixels = gdk_pixbuf_get_pixels (dest); src_pixels = gdk_pixbuf_read_pixels (src); _pixops_scale (dest_pixels, dest->width, dest->height, dest->rowstride, dest->n_channels, dest->has_alpha, src_pixels, src->width, src->height, src->rowstride, src->n_channels, src->has_alpha, dest_x, dest_y, dest_width, dest_height, offset_x, offset_y, scale_x, scale_y, (PixopsInterpType)interp_type); } /** * gdk_pixbuf_composite: * @src: a #GdkPixbuf * @dest: the #GdkPixbuf into which to render the results * @dest_x: the left coordinate for region to render * @dest_y: the top coordinate for region to render * @dest_width: the width of the region to render * @dest_height: the height of the region to render * @offset_x: the offset in the X direction (currently rounded to an integer) * @offset_y: the offset in the Y direction (currently rounded to an integer) * @scale_x: the scale factor in the X direction * @scale_y: the scale factor in the Y direction * @interp_type: the interpolation type for the transformation. * @overall_alpha: overall alpha for source image (0..255) * * Creates a transformation of the source image @src by scaling by * @scale_x and @scale_y then translating by @offset_x and @offset_y. * This gives an image in the coordinates of the destination pixbuf. * The rectangle (@dest_x, @dest_y, @dest_width, @dest_height) * is then alpha blended onto the corresponding rectangle of the * original destination image. * * When the destination rectangle contains parts not in the source * image, the data at the edges of the source image is replicated * to infinity. * * ![](composite.png) */ void gdk_pixbuf_composite (const GdkPixbuf *src, GdkPixbuf *dest, int dest_x, int dest_y, int dest_width, int dest_height, double offset_x, double offset_y, double scale_x, double scale_y, GdkInterpType interp_type, int overall_alpha) { const guint8 *src_pixels; guint8 *dest_pixels; g_return_if_fail (GDK_IS_PIXBUF (src)); g_return_if_fail (GDK_IS_PIXBUF (dest)); g_return_if_fail (dest_x >= 0 && dest_x + dest_width <= dest->width); g_return_if_fail (dest_y >= 0 && dest_y + dest_height <= dest->height); g_return_if_fail (overall_alpha >= 0 && overall_alpha <= 255); offset_x = floor (offset_x + 0.5); offset_y = floor (offset_y + 0.5); /* Force an implicit copy */ dest_pixels = gdk_pixbuf_get_pixels (dest); src_pixels = gdk_pixbuf_read_pixels (src); _pixops_composite (dest_pixels, dest->width, dest->height, dest->rowstride, dest->n_channels, dest->has_alpha, src_pixels, src->width, src->height, src->rowstride, src->n_channels, src->has_alpha, dest_x, dest_y, dest_width, dest_height, offset_x, offset_y, scale_x, scale_y, (PixopsInterpType)interp_type, overall_alpha); } /** * gdk_pixbuf_composite_color: * @src: a #GdkPixbuf * @dest: the #GdkPixbuf into which to render the results * @dest_x: the left coordinate for region to render * @dest_y: the top coordinate for region to render * @dest_width: the width of the region to render * @dest_height: the height of the region to render * @offset_x: the offset in the X direction (currently rounded to an integer) * @offset_y: the offset in the Y direction (currently rounded to an integer) * @scale_x: the scale factor in the X direction * @scale_y: the scale factor in the Y direction * @interp_type: the interpolation type for the transformation. * @overall_alpha: overall alpha for source image (0..255) * @check_x: the X offset for the checkboard (origin of checkboard is at -@check_x, -@check_y) * @check_y: the Y offset for the checkboard * @check_size: the size of checks in the checkboard (must be a power of two) * @color1: the color of check at upper left * @color2: the color of the other check * * Creates a transformation of the source image @src by scaling by * @scale_x and @scale_y then translating by @offset_x and @offset_y, * then alpha blends the rectangle (@dest_x ,@dest_y, @dest_width, * @dest_height) of the resulting image with a checkboard of the * colors @color1 and @color2 and renders it onto the destination * image. * * If the source image has no alpha channel, and @overall_alpha is 255, a fast * path is used which omits the alpha blending and just performs the scaling. * * See gdk_pixbuf_composite_color_simple() for a simpler variant of this * function suitable for many tasks. * **/ void gdk_pixbuf_composite_color (const GdkPixbuf *src, GdkPixbuf *dest, int dest_x, int dest_y, int dest_width, int dest_height, double offset_x, double offset_y, double scale_x, double scale_y, GdkInterpType interp_type, int overall_alpha, int check_x, int check_y, int check_size, guint32 color1, guint32 color2) { const guint8 *src_pixels; guint8 *dest_pixels; g_return_if_fail (GDK_IS_PIXBUF (src)); g_return_if_fail (GDK_IS_PIXBUF (dest)); g_return_if_fail (dest_x >= 0 && dest_x + dest_width <= dest->width); g_return_if_fail (dest_y >= 0 && dest_y + dest_height <= dest->height); g_return_if_fail (overall_alpha >= 0 && overall_alpha <= 255); offset_x = floor (offset_x + 0.5); offset_y = floor (offset_y + 0.5); /* Force an implicit copy */ dest_pixels = gdk_pixbuf_get_pixels (dest); src_pixels = gdk_pixbuf_read_pixels (src); _pixops_composite_color (dest_pixels, dest_width, dest_height, dest->rowstride, dest->n_channels, dest->has_alpha, src_pixels, src->width, src->height, src->rowstride, src->n_channels, src->has_alpha, dest_x, dest_y, dest_width, dest_height, offset_x, offset_y, scale_x, scale_y, (PixopsInterpType)interp_type, overall_alpha, check_x, check_y, check_size, color1, color2); } /** * gdk_pixbuf_scale_simple: * @src: a #GdkPixbuf * @dest_width: the width of destination image * @dest_height: the height of destination image * @interp_type: the interpolation type for the transformation. * * Create a new #GdkPixbuf containing a copy of @src scaled to * @dest_width x @dest_height. Leaves @src unaffected. @interp_type * should be #GDK_INTERP_NEAREST if you want maximum speed (but when * scaling down #GDK_INTERP_NEAREST is usually unusably ugly). The * default @interp_type should be #GDK_INTERP_BILINEAR which offers * reasonable quality and speed. * * You can scale a sub-portion of @src by creating a sub-pixbuf * pointing into @src; see gdk_pixbuf_new_subpixbuf(). * * If @dest_width and @dest_height are equal to the @src width and height, a * copy of @src is returned, avoiding any scaling. * * For more complicated scaling/alpha blending see gdk_pixbuf_scale() * and gdk_pixbuf_composite(). * * Return value: (transfer full): the new #GdkPixbuf, or %NULL if not enough memory could be * allocated for it. **/ GdkPixbuf * gdk_pixbuf_scale_simple (const GdkPixbuf *src, int dest_width, int dest_height, GdkInterpType interp_type) { GdkPixbuf *dest; g_return_val_if_fail (GDK_IS_PIXBUF (src), NULL); g_return_val_if_fail (dest_width > 0, NULL); g_return_val_if_fail (dest_height > 0, NULL); /* Fast path. */ if (dest_width == src->width && dest_height == src->height) return gdk_pixbuf_copy (src); dest = gdk_pixbuf_new (GDK_COLORSPACE_RGB, src->has_alpha, 8, dest_width, dest_height); if (!dest) return NULL; gdk_pixbuf_scale (src, dest, 0, 0, dest_width, dest_height, 0, 0, (double) dest_width / src->width, (double) dest_height / src->height, interp_type); return dest; } /** * gdk_pixbuf_composite_color_simple: * @src: a #GdkPixbuf * @dest_width: the width of destination image * @dest_height: the height of destination image * @interp_type: the interpolation type for the transformation. * @overall_alpha: overall alpha for source image (0..255) * @check_size: the size of checks in the checkboard (must be a power of two) * @color1: the color of check at upper left * @color2: the color of the other check * * Creates a new #GdkPixbuf by scaling @src to @dest_width x * @dest_height and alpha blending the result with a checkboard of colors * @color1 and @color2. * * Return value: (transfer full): the new #GdkPixbuf, or %NULL if not enough memory could be * allocated for it. **/ GdkPixbuf * gdk_pixbuf_composite_color_simple (const GdkPixbuf *src, int dest_width, int dest_height, GdkInterpType interp_type, int overall_alpha, int check_size, guint32 color1, guint32 color2) { GdkPixbuf *dest; g_return_val_if_fail (GDK_IS_PIXBUF (src), NULL); g_return_val_if_fail (dest_width > 0, NULL); g_return_val_if_fail (dest_height > 0, NULL); g_return_val_if_fail (overall_alpha >= 0 && overall_alpha <= 255, NULL); dest = gdk_pixbuf_new (GDK_COLORSPACE_RGB, src->has_alpha, 8, dest_width, dest_height); if (!dest) return NULL; gdk_pixbuf_composite_color (src, dest, 0, 0, dest_width, dest_height, 0, 0, (double) dest_width / src->width, (double) dest_height / src->height, interp_type, overall_alpha, 0, 0, check_size, color1, color2); return dest; } #define OFFSET(pb, x, y) ((x) * (pb)->n_channels + (gsize)(y) * (pb)->rowstride) /** * gdk_pixbuf_rotate_simple: * @src: a #GdkPixbuf * @angle: the angle to rotate by * * Rotates a pixbuf by a multiple of 90 degrees, and returns the * result in a new pixbuf. * * If @angle is 0, a copy of @src is returned, avoiding any rotation. * * Returns: (nullable) (transfer full): the new #GdkPixbuf, or %NULL * if not enough memory could be allocated for it. * * Since: 2.6 */ GdkPixbuf * gdk_pixbuf_rotate_simple (const GdkPixbuf *src, GdkPixbufRotation angle) { const guint8 *src_pixels; guint8 *dest_pixels; GdkPixbuf *dest; const guchar *p; guchar *q; gint x, y; g_return_val_if_fail (GDK_IS_PIXBUF (src), NULL); src_pixels = gdk_pixbuf_read_pixels (src); switch (angle % 360) { case 0: dest = gdk_pixbuf_copy (src); break; case 90: dest = gdk_pixbuf_new (src->colorspace, src->has_alpha, src->bits_per_sample, src->height, src->width); if (!dest) return NULL; dest_pixels = gdk_pixbuf_get_pixels (dest); for (y = 0; y < src->height; y++) { for (x = 0; x < src->width; x++) { p = src_pixels + OFFSET (src, x, y); q = dest_pixels + OFFSET (dest, y, src->width - x - 1); memcpy (q, p, dest->n_channels); } } break; case 180: dest = gdk_pixbuf_new (src->colorspace, src->has_alpha, src->bits_per_sample, src->width, src->height); if (!dest) return NULL; dest_pixels = gdk_pixbuf_get_pixels (dest); for (y = 0; y < src->height; y++) { for (x = 0; x < src->width; x++) { p = src_pixels + OFFSET (src, x, y); q = dest_pixels + OFFSET (dest, src->width - x - 1, src->height - y - 1); memcpy (q, p, dest->n_channels); } } break; case 270: dest = gdk_pixbuf_new (src->colorspace, src->has_alpha, src->bits_per_sample, src->height, src->width); if (!dest) return NULL; dest_pixels = gdk_pixbuf_get_pixels (dest); for (y = 0; y < src->height; y++) { for (x = 0; x < src->width; x++) { p = src_pixels + OFFSET (src, x, y); q = dest_pixels + OFFSET (dest, src->height - y - 1, x); memcpy (q, p, dest->n_channels); } } break; default: dest = NULL; g_warning ("gdk_pixbuf_rotate_simple() can only rotate " "by multiples of 90 degrees"); g_assert_not_reached (); } return dest; } /** * gdk_pixbuf_flip: * @src: a #GdkPixbuf * @horizontal: %TRUE to flip horizontally, %FALSE to flip vertically * * Flips a pixbuf horizontally or vertically and returns the * result in a new pixbuf. * * Returns: (nullable) (transfer full): the new #GdkPixbuf, or %NULL * if not enough memory could be allocated for it. * * Since: 2.6 */ GdkPixbuf * gdk_pixbuf_flip (const GdkPixbuf *src, gboolean horizontal) { const guint8 *src_pixels; guint8 *dest_pixels; GdkPixbuf *dest; const guchar *p; guchar *q; gint x, y; g_return_val_if_fail (GDK_IS_PIXBUF (src), NULL); dest = gdk_pixbuf_new (src->colorspace, src->has_alpha, src->bits_per_sample, src->width, src->height); if (!dest) return NULL; dest_pixels = gdk_pixbuf_get_pixels (dest); src_pixels = gdk_pixbuf_read_pixels (src); if (!horizontal) /* flip vertical */ { for (y = 0; y < dest->height; y++) { p = src_pixels + OFFSET (src, 0, y); q = dest_pixels + OFFSET (dest, 0, dest->height - y - 1); memcpy (q, p, dest->rowstride); } } else /* flip horizontal */ { for (y = 0; y < dest->height; y++) { for (x = 0; x < dest->width; x++) { p = src_pixels + OFFSET (src, x, y); q = dest_pixels + OFFSET (dest, dest->width - x - 1, y); memcpy (q, p, dest->n_channels); } } } return dest; }