music-brainz-go/libpng/img.c

#include "img.h"


image initialize_png(char *title, char *filename, int width, int height)
{
	image ret;
	FILE *fp = NULL;

	fp = fopen(filename, "wb");
	if (fp == NULL) {
		fprintf(stderr, "could not create %s", filename);
		exit(EXIT_FAILURE);
	}

	png_structp png_ptr =
	    png_create_write_struct(PNG_LIBPNG_VER_STRING,
				    NULL,
				    NULL,
				    NULL);

	if (png_ptr == NULL) {
		fprintf(stderr, "Could not create write struct. libpng\n");
	}


	png_infop info_ptr = png_create_info_struct(png_ptr);
	if (info_ptr == NULL) {
		fprintf(stderr, "Could not create info struct. libpng\n");
	}

	if (setjmp(png_jmpbuf(png_ptr))) {
		fprintf(stderr, "Error during png creation\n");
	}

	png_init_io(png_ptr, fp);

	//Write header
	png_set_IHDR(png_ptr,
		     info_ptr,
		     width,
		     height,
		     8,
		     PNG_COLOR_TYPE_RGB,
		     PNG_INTERLACE_NONE,
		     PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
	if (title != NULL) {
		png_text title_text;
		title_text.compression = PNG_TEXT_COMPRESSION_NONE;
		title_text.key = "Title";
		title_text.text = title;
		png_set_text(png_ptr, info_ptr, &title_text, 1);
	}

	png_write_info(png_ptr, info_ptr);

	ret.png_ptr = png_ptr;
	ret.info_ptr = info_ptr;
	ret.width = width;
	ret.height = height;
	ret.fp = fp;
	return ret;
}

void write_image(image * img, pix_row * img_array)
{

	png_bytep row = NULL;
	int x = 0, y = 0;
	row = (png_bytep) malloc(3 * img->width * sizeof(png_byte));
	for (y = 0; y < img->height; y++) {
		for (x = 0; x < img->width; x++) {
			row[x * 3 + 0] = img_array[x].p[y].r;	//red
			row[x * 3 + 1] = img_array[x].p[y].g;	// green
			row[x * 3 + 2] = img_array[x].p[y].b;	// blue
		}
		png_write_row(img->png_ptr, row);
	}
	png_write_end(img->png_ptr, img->info_ptr);
	free(row);
}

void finish_image(image * img)
{
	fclose(img->fp);
	png_free_data(img->png_ptr, img->info_ptr, PNG_FREE_ALL, -1);
	png_destroy_write_struct(&img->png_ptr, NULL);

}