/* $Id$ */

#include "gd.h"

#include <stdio.h>

#include <stdlib.h>

#include <math.h>

gdImagePtr loadImage(const char *name)

{

	FILE *fp;

	gdImagePtr im;

	fp = fopen(name, "rb");

	if (!fp) {

		fprintf(stderr, "Can't open jpeg file\n");

		return NULL;

	}

	im = gdImageCreateFromJpeg(fp);

	fclose(fp);

	return im;

}

int savePngImage(gdImagePtr im, const char *name)

{

	FILE *fp;

	fp = fopen(name, "wb");

	if (!fp) {

		fprintf(stderr, "Can't save png image fromtiff.png\n");

		return 0;

	}

	gdImagePng(im, fp);

	fclose(fp);

	return 1;

}

int main(int argc, char **arg)

{

	gdImagePtr im, im2;

	int new_width, new_height;

	double angle, a2;

	if (argc < 3) {

		fprintf(stderr, "Usage: copyrotated [angle in degree] [filename.png]\n");

		return 1;

	}

	angle = strtod(arg[1], 0);

	im = loadImage(arg[2]);

	if (!im) {

		fprintf(stderr, "Can't load PNG file <%s>", arg[1]);

		return 1;

	}

	/*

		cos adj hyp (cos = adjacent / hypothenus)

		sin op hyp (sin adjacent / hypothenus)

		+ 10 pixels margin

	 */

	/* to radian */

	a2 = angle * .0174532925;

	new_width = ceil(cos(a2) * gdImageSX(im)) +

	            fabs(sin(a2) * gdImageSY(im));

	new_height = ceil(cos(a2) * gdImageSY(im)) +

	             fabs(sin(a2) * gdImageSX(im));

	im2 = gdImageCreateTrueColor(new_width, new_height);

	if (!im2) {

		fprintf(stderr, "Can't create a new image");

		gdImageDestroy(im);

		return 1;

	}

	gdImageAlphaBlending(im2, 0);

	gdImageFilledRectangle(im2, 0, 0, gdImageSX(im2), gdImageSY(im2), gdTrueColorAlpha(127,0,0,127));

	gdImageCopyRotated(im2, im, new_width/2, new_height/2, 0, 0, gdImageSX(im), gdImageSY(im), angle);

	gdImageSaveAlpha(im2, 1);

	if (!savePngImage(im2, "rotated.png")) {

		fprintf(stderr, "Can't save PNG file rotated.png");

		gdImageDestroy(im);

		gdImageDestroy(im2);

		return 1;

	}

	gdImageDestroy(im2);

	gdImageDestroy(im);

	return 0;

}