basic png support

2 files changed, 61 insertions, 2 deletions

diff --git a/Makefile b/Makefile
index 1b0e819..50dc6b8 100644
--- a/Makefile
+++ b/Makefile
@@ -7,7 +7,7 @@ OBJFILES := $(SRCFILES:%.c=%.o)
 DEPFILES := $(OBJFILES:%.o=%.d)
 CLEANFILES := $(CLEANFILES) $(DEPFILES) $(OBJFILES) meh
 CFLAGS := -O3 -Wall -g -ggdb
-LIBS := -lX11 -ljpeg
+LIBS := -lX11 -ljpeg -lpng
 
 meh: $(OBJFILES)
 	$(CC) -o $@ $(OBJFILES) $(LIBS)
diff --git a/src/png.c b/src/png.c
index 76b4461..b814fc4 100644
--- a/src/png.c
+++ b/src/png.c
@@ -1,6 +1,65 @@
+#include <png.h>
+
 #include "meh.h"
 
 unsigned char *loadpng(FILE *infile, int *bufwidth, int *bufheight){
-	return NULL;
+	png_structp png_ptr;
+	png_infop info_ptr;
+	png_infop end_info;
+	int numpasses = 1;
+	unsigned char *buf;
+	
+	if((png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL)) == NULL)
+		return NULL;
+	if((info_ptr = png_create_info_struct(png_ptr)) == NULL){
+		png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
+		return NULL;
+	}
+	if((end_info = png_create_info_struct(png_ptr)) == NULL){
+		png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
+		return NULL;
+	}
+	if(setjmp(png_jmpbuf(png_ptr))){
+		png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
+		return NULL;
+	}
+
+	png_init_io(png_ptr, infile);
+
+	/* Start reading */
+	png_read_info(png_ptr, info_ptr);
+	buf = malloc(100);
+	{
+		png_byte color_type = png_get_color_type(png_ptr, info_ptr);
+		if(color_type == PNG_COLOR_TYPE_PALETTE)
+			png_set_palette_to_rgb(png_ptr);
+		if(color_type == PNG_COLOR_TYPE_GRAY && png_get_bit_depth(png_ptr, info_ptr) < 8)
+			png_set_gray_1_2_4_to_8(png_ptr);
+		if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
+			png_set_tRNS_to_alpha(png_ptr);
+		if (png_get_bit_depth(png_ptr, info_ptr) == 16)
+			png_set_strip_16(png_ptr);
+		if(color_type & PNG_COLOR_MASK_ALPHA)
+			png_set_strip_alpha(png_ptr);
+		if (color_type == PNG_COLOR_TYPE_GRAY || color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+			png_set_gray_to_rgb(png_ptr);
+		if(png_get_interlace_type == PNG_INTERLACE_ADAM7)
+			numpasses = png_set_interlace_handling(png_ptr);
+		png_read_update_info(png_ptr, info_ptr);
+	}
+	{
+		int y;
+		*bufwidth = png_get_image_width(png_ptr, info_ptr);
+		*bufheight = png_get_image_height(png_ptr, info_ptr);
+		buf = malloc((*bufwidth) * (*bufheight) * 3);
+		printf("%ix%i\n", *bufwidth, *bufheight);
+		while(numpasses--){
+			for(y = 0; y < *bufheight; y++)
+				png_read_row(png_ptr, &buf[y * (*bufwidth) * 3], NULL);
+		}
+	}
+
+	printf("reached end\n");
+	return buf;
 }