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#include <glib.h>
#include <stdio.h>
#include <string.h>
#include "jpeg_rgb_internal.h"
#include "jpeg.h"
static void convert (JpegRGBDecoder * rgbdec);
static void imagescale2h_u8 (unsigned char *dest, int d_rowstride,
unsigned char *src, int src_rowstride, int width, int height);
static void imagescale2v_u8 (unsigned char *dest, int d_rowstride,
unsigned char *src, int src_rowstride, int width, int height);
static void imagescale2h2v_u8 (unsigned char *dest, int d_rowstride,
unsigned char *src, int src_rowstride, int width, int height);
static void scanlinescale2_u8 (unsigned char *dest, unsigned char *src,
int len);
JpegRGBDecoder *
jpeg_rgb_decoder_new (void)
{
JpegRGBDecoder *rgbdec;
rgbdec = g_new0 (JpegRGBDecoder, 1);
rgbdec->dec = jpeg_decoder_new ();
return rgbdec;
}
void
jpeg_rgb_decoder_free (JpegRGBDecoder * rgbdec)
{
int i;
jpeg_decoder_free (rgbdec->dec);
for (i = 0; i < 3; i++) {
if (rgbdec->component[i].alloc) {
g_free (rgbdec->component[i].image);
}
}
g_free (rgbdec);
}
int
jpeg_rgb_decoder_addbits (JpegRGBDecoder * dec, unsigned char *data,
unsigned int len)
{
return jpeg_decoder_addbits (dec->dec, data, len);
}
int
jpeg_rgb_decoder_parse (JpegRGBDecoder * dec)
{
return jpeg_decoder_parse (dec->dec);
}
int
jpeg_rgb_decoder_get_image (JpegRGBDecoder * rgbdec,
unsigned char **image, int *rowstride, int *width, int *height)
{
int i;
jpeg_decoder_get_image_size (rgbdec->dec, &rgbdec->width, &rgbdec->height);
for (i = 0; i < 3; i++) {
jpeg_decoder_get_component_ptr (rgbdec->dec, i + 1,
&rgbdec->component[i].image, &rgbdec->component[i].rowstride);
jpeg_decoder_get_component_subsampling (rgbdec->dec, i + 1,
&rgbdec->component[i].h_subsample, &rgbdec->component[i].v_subsample);
rgbdec->component[i].alloc = 0;
if (rgbdec->component[i].h_subsample > 1 ||
rgbdec->component[i].v_subsample > 1) {
unsigned char *dest;
dest = g_malloc (rgbdec->width * rgbdec->height);
if (rgbdec->component[i].v_subsample > 1) {
if (rgbdec->component[i].h_subsample > 1) {
imagescale2h2v_u8 (dest,
rgbdec->width,
rgbdec->component[i].image,
rgbdec->component[i].rowstride, rgbdec->width, rgbdec->height);
} else {
imagescale2v_u8 (dest,
rgbdec->width,
rgbdec->component[i].image,
rgbdec->component[i].rowstride, rgbdec->width, rgbdec->height);
}
} else {
imagescale2h_u8 (dest,
rgbdec->width,
rgbdec->component[i].image,
rgbdec->component[i].rowstride, rgbdec->width, rgbdec->height);
}
rgbdec->component[i].alloc = 1;
rgbdec->component[i].image = dest;
rgbdec->component[i].rowstride = rgbdec->width;
rgbdec->component[i].h_subsample = 1;
rgbdec->component[i].v_subsample = 1;
}
}
rgbdec->image = g_malloc (rgbdec->width * rgbdec->height * 4);
convert (rgbdec);
if (image)
*image = rgbdec->image;
if (rowstride)
*rowstride = rgbdec->width * 4;
if (width)
*width = rgbdec->width;
if (height)
*height = rgbdec->height;
return 0;
}
/* from the JFIF spec */
#define YUV_TO_R(y,u,v) CLAMP((y) + 1.402*((v)-128),0,255)
#define YUV_TO_G(y,u,v) CLAMP((y) - 0.34414*((u)-128) - 0.71414*((v)-128),0,255)
#define YUV_TO_B(y,u,v) CLAMP((y) + 1.772*((u)-128),0,255)
static void
convert (JpegRGBDecoder * rgbdec)
{
int x, y;
unsigned char *yp;
unsigned char *up;
unsigned char *vp;
unsigned char *rgbp;
rgbp = rgbdec->image;
yp = rgbdec->component[0].image;
up = rgbdec->component[1].image;
vp = rgbdec->component[2].image;
for (y = 0; y < rgbdec->height; y++) {
for (x = 0; x < rgbdec->width; x++) {
rgbp[0] = YUV_TO_B (yp[x], up[x], vp[x]);
rgbp[1] = YUV_TO_G (yp[x], up[x], vp[x]);
rgbp[2] = YUV_TO_R (yp[x], up[x], vp[x]);
rgbp[3] = 0;
rgbp += 4;
}
yp += rgbdec->component[0].rowstride;
up += rgbdec->component[1].rowstride;
vp += rgbdec->component[2].rowstride;
}
}
static void
imagescale2h_u8 (unsigned char *dest, int d_rowstride,
unsigned char *src, int s_rowstride, int width, int height)
{
int i;
for (i = 0; i < height; i++) {
scanlinescale2_u8 (dest + i * d_rowstride, src + i * s_rowstride, width);
}
}
static void
imagescale2v_u8 (unsigned char *dest, int d_rowstride,
unsigned char *src, int s_rowstride, int width, int height)
{
int i;
for (i = 0; i < height; i++) {
memcpy (dest + i * d_rowstride, src + (i / 2) * s_rowstride, width);
}
}
static void
imagescale2h2v_u8 (unsigned char *dest, int d_rowstride,
unsigned char *src, int s_rowstride, int width, int height)
{
int i;
for (i = 0; i < height; i++) {
scanlinescale2_u8 (dest + i * d_rowstride,
src + (i / 2) * s_rowstride, width);
}
}
static void
scanlinescale2_u8 (unsigned char *dest, unsigned char *src, int len)
{
int i;
for (i = 0; i < len; i++) {
dest[i] = src[i / 2];
}
}
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