libgd/examples/copyrotated.c

91 lines
1.8 KiB
C

#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 / hypotenuse)
sin op hyp (sin adjacent / hypotenuse)
+ 10 pixels margin
*/
/* to radian */
a2 = angle * .0174532925;
new_width = fabs(ceil(cos(a2) * gdImageSX(im))) +
fabs(sin(a2) * gdImageSY(im));
new_height = fabs(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;
}