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snes9xgx/source/ngc/pngu.c
michniewski 043e3ee61d - working on new gui 
- video patch 1
2008-09-09 03:02:11 +00:00

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/********************************************************************************************
PNGU Version : 0.2a
Coder : frontier
More info : http://frontier-dev.net
********************************************************************************************/
#include <stdio.h>
#include <malloc.h>
#include <pngu/pngu.h>
#include <png.h>
// Constants
#define PNGU_SOURCE_BUFFER 1
#define PNGU_SOURCE_DEVICE 2
// Prototypes of helper functions
int pngu_info (IMGCTX ctx);
int pngu_decode (IMGCTX ctx, PNGU_u32 width, PNGU_u32 height, PNGU_u32 stripAlpha);
void pngu_free_info (IMGCTX ctx);
void pngu_read_data_from_buffer (png_structp png_ptr, png_bytep data, png_size_t length);
void pngu_write_data_to_buffer (png_structp png_ptr, png_bytep data, png_size_t length);
void pngu_flush_data_to_buffer (png_structp png_ptr);
int pngu_clamp (int value, int min, int max);
// PNGU Image context struct
struct _IMGCTX
{
int source;
void *buffer;
char *filename;
PNGU_u32 cursor;
PNGU_u32 propRead;
PNGUPROP prop;
PNGU_u32 infoRead;
png_structp png_ptr;
png_infop info_ptr;
FILE *fd;
png_bytep *row_pointers;
png_bytep img_data;
};
// PNGU Implementation //
IMGCTX PNGU_SelectImageFromBuffer (const void *buffer)
{
IMGCTX ctx = NULL;
if (!buffer)
return NULL;
ctx = malloc (sizeof (struct _IMGCTX));
if (!ctx)
return NULL;
ctx->buffer = (void *) buffer;
ctx->source = PNGU_SOURCE_BUFFER;
ctx->cursor = 0;
ctx->filename = NULL;
ctx->propRead = 0;
ctx->infoRead = 0;
return ctx;
}
IMGCTX PNGU_SelectImageFromDevice (const char *filename)
{
IMGCTX ctx = NULL;
if (!filename)
return NULL;
ctx = malloc (sizeof (struct _IMGCTX));
if (!ctx)
return NULL;
ctx->buffer = NULL;
ctx->source = PNGU_SOURCE_DEVICE;
ctx->cursor = 0;
ctx->filename = malloc (strlen (filename) + 1);
if (!ctx->filename)
{
free (ctx);
return NULL;
}
strcpy(ctx->filename, filename);
ctx->propRead = 0;
ctx->infoRead = 0;
return ctx;
}
void PNGU_ReleaseImageContext (IMGCTX ctx)
{
if (!ctx)
return;
if (ctx->filename)
free (ctx->filename);
if ((ctx->propRead) && (ctx->prop.trans))
free (ctx->prop.trans);
pngu_free_info (ctx);
free (ctx);
}
int PNGU_GetImageProperties (IMGCTX ctx, PNGUPROP *imgprop)
{
int res;
if (!ctx->propRead)
{
res = pngu_info (ctx);
if (res != PNGU_OK)
return res;
}
*imgprop = ctx->prop;
return PNGU_OK;
}
int PNGU_DecodeToYCbYCr (IMGCTX ctx, PNGU_u32 width, PNGU_u32 height, void *buffer, PNGU_u32 stride)
{
int result;
PNGU_u32 x, y, buffWidth;
// width needs to be divisible by two
if (width % 2)
return PNGU_ODD_WIDTH;
// stride needs to be divisible by two
if (stride % 2)
return PNGU_ODD_STRIDE;
result = pngu_decode (ctx, width, height, 1);
if (result != PNGU_OK)
return result;
// Copy image to the output buffer
buffWidth = (width + stride) / 2;
for (y = 0; y < height; y++)
for (x = 0; x < (width / 2); x++)
((PNGU_u32 *)buffer)[y*buffWidth+x] = PNGU_RGB8_TO_YCbYCr (*(ctx->row_pointers[y]+x*6), *(ctx->row_pointers[y]+x*6+1), *(ctx->row_pointers[y]+x*6+2),
*(ctx->row_pointers[y]+x*6+3), *(ctx->row_pointers[y]+x*6+4), *(ctx->row_pointers[y]+x*6+5));
// Free resources
free (ctx->img_data);
free (ctx->row_pointers);
// Success
return PNGU_OK;
}
int PNGU_DecodeToRGB565 (IMGCTX ctx, PNGU_u32 width, PNGU_u32 height, void *buffer, PNGU_u32 stride)
{
int result;
PNGU_u32 x, y, buffWidth;
result = pngu_decode (ctx, width, height, 1);
if (result != PNGU_OK)
return result;
buffWidth = width + stride;
// Copy image to the output buffer
for (y = 0; y < height; y++)
for (x = 0; x < width; x++)
((PNGU_u16 *)buffer)[y*buffWidth+x] =
(((PNGU_u16) (ctx->row_pointers[y][x*3] & 0xF8)) << 8) |
(((PNGU_u16) (ctx->row_pointers[y][x*3+1] & 0xFC)) << 3) |
(((PNGU_u16) (ctx->row_pointers[y][x*3+2] & 0xF8)) >> 3);
// Free resources
free (ctx->img_data);
free (ctx->row_pointers);
// Success
return PNGU_OK;
}
int PNGU_DecodeToRGBA8 (IMGCTX ctx, PNGU_u32 width, PNGU_u32 height, void *buffer, PNGU_u32 stride, PNGU_u8 default_alpha)
{
int result;
PNGU_u32 x, y, buffWidth;
result = pngu_decode (ctx, width, height, 0);
if (result != PNGU_OK)
return result;
buffWidth = width + stride;
// Check is source image has an alpha channel
if ( (ctx->prop.imgColorType == PNGU_COLOR_TYPE_GRAY_ALPHA) || (ctx->prop.imgColorType == PNGU_COLOR_TYPE_RGB_ALPHA) )
{
// Alpha channel present, copy image to the output buffer
for (y = 0; y < height; y++)
memcpy (buffer + (y * buffWidth * 4), ctx->row_pointers[y], width * 4);
}
else
{
// No alpha channel present, copy image to the output buffer
for (y = 0; y < height; y++)
for (x = 0; x < width; x++)
((PNGU_u32 *)buffer)[y*buffWidth+x] =
(((PNGU_u32) ctx->row_pointers[y][x*3]) << 24) |
(((PNGU_u32) ctx->row_pointers[y][x*3+1]) << 16) |
(((PNGU_u32) ctx->row_pointers[y][x*3+2]) << 8) |
((PNGU_u32) default_alpha);
}
// Free resources
free (ctx->img_data);
free (ctx->row_pointers);
// Success
return PNGU_OK;
}
int PNGU_DecodeTo4x4RGB565 (IMGCTX ctx, PNGU_u32 width, PNGU_u32 height, void *buffer)
{
int result;
PNGU_u32 x, y, qwidth, qheight;
// width and height need to be divisible by four
if ((width % 4) || (height % 4))
return PNGU_INVALID_WIDTH_OR_HEIGHT;
result = pngu_decode (ctx, width, height, 1);
if (result != PNGU_OK)
return result;
// Copy image to the output buffer
qwidth = width / 4;
qheight = height / 4;
for (y = 0; y < qheight; y++)
for (x = 0; x < qwidth; x++)
{
int blockbase = (y * qwidth + x) * 4;
PNGU_u64 field64 = *((PNGU_u64 *)(ctx->row_pointers[y*4]+x*12));
PNGU_u64 field32 = (PNGU_u64) *((PNGU_u32 *)(ctx->row_pointers[y*4]+x*12+8));
((PNGU_u64 *) buffer)[blockbase] =
(((field64 & 0xF800000000000000ULL) | ((field64 & 0xFC000000000000ULL) << 3) | ((field64 & 0xF80000000000ULL) << 5)) |
(((field64 & 0xF800000000ULL) << 8) | ((field64 & 0xFC000000ULL) << 11) | ((field64 & 0xF80000ULL) << 13)) |
(((field64 & 0xF800ULL) << 16) | ((field64 & 0xFCULL) << 19) | ((field32 & 0xF8000000ULL) >> 11)) |
(((field32 & 0xF80000ULL) >> 8) | ((field32 & 0xFC00ULL) >> 5) | ((field32 & 0xF8ULL) >> 3)));
field64 = *((PNGU_u64 *)(ctx->row_pointers[y*4+1]+x*12));
field32 = (PNGU_u64) *((PNGU_u32 *)(ctx->row_pointers[y*4+1]+x*12+8));
((PNGU_u64 *) buffer)[blockbase+1] =
(((field64 & 0xF800000000000000ULL) | ((field64 & 0xFC000000000000ULL) << 3) | ((field64 & 0xF80000000000ULL) << 5)) |
(((field64 & 0xF800000000ULL) << 8) | ((field64 & 0xFC000000ULL) << 11) | ((field64 & 0xF80000ULL) << 13)) |
(((field64 & 0xF800ULL) << 16) | ((field64 & 0xFCULL) << 19) | ((field32 & 0xF8000000ULL) >> 11)) |
(((field32 & 0xF80000ULL) >> 8) | ((field32 & 0xFC00ULL) >> 5) | ((field32 & 0xF8ULL) >> 3)));
field64 = *((PNGU_u64 *)(ctx->row_pointers[y*4+2]+x*12));
field32 = (PNGU_u64) *((PNGU_u32 *)(ctx->row_pointers[y*4+2]+x*12+8));
((PNGU_u64 *) buffer)[blockbase+2] =
(((field64 & 0xF800000000000000ULL) | ((field64 & 0xFC000000000000ULL) << 3) | ((field64 & 0xF80000000000ULL) << 5)) |
(((field64 & 0xF800000000ULL) << 8) | ((field64 & 0xFC000000ULL) << 11) | ((field64 & 0xF80000ULL) << 13)) |
(((field64 & 0xF800ULL) << 16) | ((field64 & 0xFCULL) << 19) | ((field32 & 0xF8000000ULL) >> 11)) |
(((field32 & 0xF80000ULL) >> 8) | ((field32 & 0xFC00ULL) >> 5) | ((field32 & 0xF8ULL) >> 3)));
field64 = *((PNGU_u64 *)(ctx->row_pointers[y*4+3]+x*12));
field32 = (PNGU_u64) *((PNGU_u32 *)(ctx->row_pointers[y*4+3]+x*12+8));
((PNGU_u64 *) buffer)[blockbase+3] =
(((field64 & 0xF800000000000000ULL) | ((field64 & 0xFC000000000000ULL) << 3) | ((field64 & 0xF80000000000ULL) << 5)) |
(((field64 & 0xF800000000ULL) << 8) | ((field64 & 0xFC000000ULL) << 11) | ((field64 & 0xF80000ULL) << 13)) |
(((field64 & 0xF800ULL) << 16) | ((field64 & 0xFCULL) << 19) | ((field32 & 0xF8000000ULL) >> 11)) |
(((field32 & 0xF80000ULL) >> 8) | ((field32 & 0xFC00ULL) >> 5) | ((field32 & 0xF8ULL) >> 3)));
}
// Free resources
free (ctx->img_data);
free (ctx->row_pointers);
// Success
return PNGU_OK;
}
int PNGU_DecodeTo4x4RGB5A3 (IMGCTX ctx, PNGU_u32 width, PNGU_u32 height, void *buffer, PNGU_u8 default_alpha)
{
int result;
PNGU_u32 x, y, qwidth, qheight;
PNGU_u64 alphaMask;
// width and height need to be divisible by four
if ((width % 4) || (height % 4))
return PNGU_INVALID_WIDTH_OR_HEIGHT;
result = pngu_decode (ctx, width, height, 0);
if (result != PNGU_OK)
return result;
// Init some vars
qwidth = width / 4;
qheight = height / 4;
// Check is source image has an alpha channel
if ( (ctx->prop.imgColorType == PNGU_COLOR_TYPE_GRAY_ALPHA) || (ctx->prop.imgColorType == PNGU_COLOR_TYPE_RGB_ALPHA) )
{
// Alpha channel present, copy image to the output buffer
for (y = 0; y < qheight; y++)
for (x = 0; x < qwidth; x++)
{
int blockbase = (y * qwidth + x) * 4;
PNGU_u64 tmp;
PNGU_u64 fieldA = *((PNGU_u64 *)(ctx->row_pointers[y*4]+x*16));
PNGU_u64 fieldB = *((PNGU_u64 *)(ctx->row_pointers[y*4]+x*16+8));
// If first pixel is opaque set MSB to 1 and encode colors in RGB555, else set MSB to 0 and encode colors in ARGB3444
if ((fieldA & 0xE000000000ULL) == 0xE000000000ULL)
tmp = 0x8000000000000000ULL | ((fieldA & 0xF800000000000000ULL) >> 1) | ((fieldA & 0xF8000000000000ULL) << 2) | ((fieldA & 0xF80000000000ULL) << 5);
else
tmp = ((fieldA & 0xE000000000ULL) << 23) | ((fieldA & 0xF000000000000000ULL) >> 4) | (fieldA & 0xF0000000000000ULL) | ((fieldA & 0xF00000000000ULL) << 4);
// If second pixel is opaque set MSB to 1 and encode colors in RGB555, else set MSB to 0 and encode colors in ARGB3444
if ((fieldA & 0xE0ULL) == 0xE0ULL)
tmp = tmp | 0x800000000000ULL | ((fieldA & 0xF8000000ULL) << 15) | ((fieldA & 0xF80000ULL) << 18) | ((fieldA & 0xF800ULL) << 21);
else
tmp = tmp | ((fieldA & 0xE0ULL) << 39) | ((fieldA & 0xF0000000ULL) << 12) | ((fieldA & 0xF00000ULL) << 16) | ((fieldA & 0xF000ULL) << 20);
// If third pixel is opaque set MSB to 1 and encode colors in RGB555, else set MSB to 0 and encode colors in ARGB3444
if ((fieldB & 0xE000000000ULL) == 0xE000000000ULL)
tmp = tmp | 0x80000000ULL | ((fieldB & 0xF800000000000000ULL) >> 33) | ((fieldB & 0xF8000000000000ULL) >> 30) | ((fieldB & 0xF80000000000ULL) >> 27);
else
tmp = tmp | ((fieldB & 0xE000000000ULL) >> 9) | ((fieldB & 0xF000000000000000ULL) >> 36) | ((fieldB & 0xF0000000000000ULL) >> 32) | ((fieldB & 0xF00000000000ULL) >> 28);
// If fourth pixel is opaque set MSB to 1 and encode colors in RGB555, else set MSB to 0 and encode colors in ARGB3444
if ((fieldB & 0xE0ULL) == 0xE0ULL)
tmp = tmp | 0x8000ULL | ((fieldB & 0xF8000000ULL) >> 17) | ((fieldB & 0xF80000ULL) >> 14) | ((fieldB & 0xF800ULL) >> 11);
else
tmp = tmp | ((fieldB & 0xE0ULL) << 7) | ((fieldB & 0xF0000000ULL) >> 20) | ((fieldB & 0xF00000ULL) >> 16) | ((fieldB & 0xF000ULL) >> 12);
((PNGU_u64 *) buffer)[blockbase] = tmp;
fieldA = *((PNGU_u64 *)(ctx->row_pointers[y*4+1]+x*16));
fieldB = *((PNGU_u64 *)(ctx->row_pointers[y*4+1]+x*16+8));
if ((fieldA & 0xE000000000ULL) == 0xE000000000ULL)
// Opaque pixel, so set MSB to 1 and encode colors in RGB555
tmp = 0x8000000000000000ULL | ((fieldA & 0xF800000000000000ULL) >> 1) | ((fieldA & 0xF8000000000000ULL) << 2) | ((fieldA & 0xF80000000000ULL) << 5);
else
// Tranlucid pixel, so set MSB to 0 and encode colors in ARGB3444
tmp = ((fieldA & 0xE000000000ULL) << 23) | ((fieldA & 0xF000000000000000ULL) >> 4) | (fieldA & 0xF0000000000000ULL) | ((fieldA & 0xF00000000000ULL) << 4);
if ((fieldA & 0xE0ULL) == 0xE0ULL)
// Opaque pixel, so set MSB to 1 and encode colors in RGB555
tmp = tmp | 0x800000000000ULL | ((fieldA & 0xF8000000ULL) << 15) | ((fieldA & 0xF80000ULL) << 18) | ((fieldA & 0xF800ULL) << 21);
else
// Tranlucid pixel, so set MSB to 0 and encode colors in ARGB3444
tmp = tmp | ((fieldA & 0xE0ULL) << 39) | ((fieldA & 0xF0000000ULL) << 12) | ((fieldA & 0xF00000ULL) << 16) | ((fieldA & 0xF000ULL) << 20);
if ((fieldB & 0xE000000000ULL) == 0xE000000000ULL)
// Opaque pixel, so set MSB to 1 and encode colors in RGB555
tmp = tmp | 0x80000000ULL | ((fieldB & 0xF800000000000000ULL) >> 33) | ((fieldB & 0xF8000000000000ULL) >> 30) | ((fieldB & 0xF80000000000ULL) >> 27);
else
// Tranlucid pixel, so set MSB to 0 and encode colors in ARGB3444
tmp = tmp | ((fieldB & 0xE000000000ULL) >> 9) | ((fieldB & 0xF000000000000000ULL) >> 36) | ((fieldB & 0xF0000000000000ULL) >> 32) | ((fieldB & 0xF00000000000ULL) >> 28);
if ((fieldB & 0xE0ULL) == 0xE0ULL)
// Opaque pixel, so set MSB to 1 and encode colors in RGB555
tmp = tmp | 0x8000ULL | ((fieldB & 0xF8000000ULL) >> 17) | ((fieldB & 0xF80000ULL) >> 14) | ((fieldB & 0xF800ULL) >> 11);
else
// Tranlucid pixel, so set MSB to 0 and encode colors in ARGB3444
tmp = tmp | ((fieldB & 0xE0ULL) << 7) | ((fieldB & 0xF0000000ULL) >> 20) | ((fieldB & 0xF00000ULL) >> 16) | ((fieldB & 0xF000ULL) >> 12);
((PNGU_u64 *) buffer)[blockbase+1] = tmp;
fieldA = *((PNGU_u64 *)(ctx->row_pointers[y*4+2]+x*16));
fieldB = *((PNGU_u64 *)(ctx->row_pointers[y*4+2]+x*16+8));
if ((fieldA & 0xE000000000ULL) == 0xE000000000ULL)
// Opaque pixel, so set MSB to 1 and encode colors in RGB555
tmp = 0x8000000000000000ULL | ((fieldA & 0xF800000000000000ULL) >> 1) | ((fieldA & 0xF8000000000000ULL) << 2) | ((fieldA & 0xF80000000000ULL) << 5);
else
// Tranlucid pixel, so set MSB to 0 and encode colors in ARGB3444
tmp = ((fieldA & 0xE000000000ULL) << 23) | ((fieldA & 0xF000000000000000ULL) >> 4) | (fieldA & 0xF0000000000000ULL) | ((fieldA & 0xF00000000000ULL) << 4);
if ((fieldA & 0xE0ULL) == 0xE0ULL)
// Opaque pixel, so set MSB to 1 and encode colors in RGB555
tmp = tmp | 0x800000000000ULL | ((fieldA & 0xF8000000ULL) << 15) | ((fieldA & 0xF80000ULL) << 18) | ((fieldA & 0xF800ULL) << 21);
else
// Tranlucid pixel, so set MSB to 0 and encode colors in ARGB3444
tmp = tmp | ((fieldA & 0xE0ULL) << 39) | ((fieldA & 0xF0000000ULL) << 12) | ((fieldA & 0xF00000ULL) << 16) | ((fieldA & 0xF000ULL) << 20);
if ((fieldB & 0xE000000000ULL) == 0xE000000000ULL)
// Opaque pixel, so set MSB to 1 and encode colors in RGB555
tmp = tmp | 0x80000000ULL | ((fieldB & 0xF800000000000000ULL) >> 33) | ((fieldB & 0xF8000000000000ULL) >> 30) | ((fieldB & 0xF80000000000ULL) >> 27);
else
// Tranlucid pixel, so set MSB to 0 and encode colors in ARGB3444
tmp = tmp | ((fieldB & 0xE000000000ULL) >> 9) | ((fieldB & 0xF000000000000000ULL) >> 36) | ((fieldB & 0xF0000000000000ULL) >> 32) | ((fieldB & 0xF00000000000ULL) >> 28);
if ((fieldB & 0xE0ULL) == 0xE0ULL)
// Opaque pixel, so set MSB to 1 and encode colors in RGB555
tmp = tmp | 0x8000ULL | ((fieldB & 0xF8000000ULL) >> 17) | ((fieldB & 0xF80000ULL) >> 14) | ((fieldB & 0xF800ULL) >> 11);
else
// Tranlucid pixel, so set MSB to 0 and encode colors in ARGB3444
tmp = tmp | ((fieldB & 0xE0ULL) << 7) | ((fieldB & 0xF0000000ULL) >> 20) | ((fieldB & 0xF00000ULL) >> 16) | ((fieldB & 0xF000ULL) >> 12);
((PNGU_u64 *) buffer)[blockbase+2] = tmp;
fieldA = *((PNGU_u64 *)(ctx->row_pointers[y*4+3]+x*16));
fieldB = *((PNGU_u64 *)(ctx->row_pointers[y*4+3]+x*16+8));
if ((fieldA & 0xE000000000ULL) == 0xE000000000ULL)
// Opaque pixel, so set MSB to 1 and encode colors in RGB555
tmp = 0x8000000000000000ULL | ((fieldA & 0xF800000000000000ULL) >> 1) | ((fieldA & 0xF8000000000000ULL) << 2) | ((fieldA & 0xF80000000000ULL) << 5);
else
// Tranlucid pixel, so set MSB to 0 and encode colors in ARGB3444
tmp = ((fieldA & 0xE000000000ULL) << 23) | ((fieldA & 0xF000000000000000ULL) >> 4) | (fieldA & 0xF0000000000000ULL) | ((fieldA & 0xF00000000000ULL) << 4);
if ((fieldA & 0xE0ULL) == 0xE0ULL)
// Opaque pixel, so set MSB to 1 and encode colors in RGB555
tmp = tmp | 0x800000000000ULL | ((fieldA & 0xF8000000ULL) << 15) | ((fieldA & 0xF80000ULL) << 18) | ((fieldA & 0xF800ULL) << 21);
else
// Tranlucid pixel, so set MSB to 0 and encode colors in ARGB3444
tmp = tmp | ((fieldA & 0xE0ULL) << 39) | ((fieldA & 0xF0000000ULL) << 12) | ((fieldA & 0xF00000ULL) << 16) | ((fieldA & 0xF000ULL) << 20);
if ((fieldB & 0xE000000000ULL) == 0xE000000000ULL)
// Opaque pixel, so set MSB to 1 and encode colors in RGB555
tmp = tmp | 0x80000000ULL | ((fieldB & 0xF800000000000000ULL) >> 33) | ((fieldB & 0xF8000000000000ULL) >> 30) | ((fieldB & 0xF80000000000ULL) >> 27);
else
// Tranlucid pixel, so set MSB to 0 and encode colors in ARGB3444
tmp = tmp | ((fieldB & 0xE000000000ULL) >> 9) | ((fieldB & 0xF000000000000000ULL) >> 36) | ((fieldB & 0xF0000000000000ULL) >> 32) | ((fieldB & 0xF00000000000ULL) >> 28);
if ((fieldB & 0xE0ULL) == 0xE0ULL)
// Opaque pixel, so set MSB to 1 and encode colors in RGB555
tmp = tmp | 0x8000ULL | ((fieldB & 0xF8000000ULL) >> 17) | ((fieldB & 0xF80000ULL) >> 14) | ((fieldB & 0xF800ULL) >> 11);
else
// Tranlucid pixel, so set MSB to 0 and encode colors in ARGB3444
tmp = tmp | ((fieldB & 0xE0ULL) << 7) | ((fieldB & 0xF0000000ULL) >> 20) | ((fieldB & 0xF00000ULL) >> 16) | ((fieldB & 0xF000ULL) >> 12);
((PNGU_u64 *) buffer)[blockbase+3] = tmp;
}
}
else
{
// No alpha channel present, copy image to the output buffer
default_alpha = (default_alpha >> 5);
if (default_alpha == 7)
{
// The user wants an opaque texture, so set MSB to 1 and encode colors in RGB555
alphaMask = 0x8000800080008000ULL;
for (y = 0; y < qheight; y++)
for (x = 0; x < qwidth; x++)
{
int blockbase = (y * qwidth + x) * 4;
PNGU_u64 field64 = *((PNGU_u64 *)(ctx->row_pointers[y*4]+x*12));
PNGU_u64 field32 = (PNGU_u64) *((PNGU_u32 *)(ctx->row_pointers[y*4]+x*12+8));
((PNGU_u64 *) buffer)[blockbase] =
alphaMask | ((field64 & 0xF800000000000000ULL) >> 1) | ((field64 & 0xF8000000000000ULL) << 2) |
((field64 & 0xF80000000000ULL) << 5) | ((field64 & 0xF800000000ULL) << 7) | ((field64 & 0xF8000000ULL) << 10) |
((field64 & 0xF80000ULL) << 13) | ((field64 & 0xF800ULL) << 15) | ((field64 & 0xF8ULL) << 18) |
((field32 & 0xF8000000ULL) >> 11) | ((field32 & 0xF80000ULL) >> 9) | ((field32 & 0xF800ULL) >> 6) | ((field32 & 0xF8ULL) >> 3);
field64 = *((PNGU_u64 *)(ctx->row_pointers[y*4+1]+x*12));
field32 = (PNGU_u64) *((PNGU_u32 *)(ctx->row_pointers[y*4+1]+x*12+8));
((PNGU_u64 *) buffer)[blockbase+1] =
alphaMask | ((field64 & 0xF800000000000000ULL) >> 1) | ((field64 & 0xF8000000000000ULL) << 2) |
((field64 & 0xF80000000000ULL) << 5) | ((field64 & 0xF800000000ULL) << 7) | ((field64 & 0xF8000000ULL) << 10) |
((field64 & 0xF80000ULL) << 13) | ((field64 & 0xF800ULL) << 15) | ((field64 & 0xF8ULL) << 18) |
((field32 & 0xF8000000ULL) >> 11) | ((field32 & 0xF80000ULL) >> 9) | ((field32 & 0xF800ULL) >> 6) | ((field32 & 0xF8ULL) >> 3);
field64 = *((PNGU_u64 *)(ctx->row_pointers[y*4+2]+x*12));
field32 = (PNGU_u64) *((PNGU_u32 *)(ctx->row_pointers[y*4+2]+x*12+8));
((PNGU_u64 *) buffer)[blockbase+2] =
alphaMask | ((field64 & 0xF800000000000000ULL) >> 1) | ((field64 & 0xF8000000000000ULL) << 2) |
((field64 & 0xF80000000000ULL) << 5) | ((field64 & 0xF800000000ULL) << 7) | ((field64 & 0xF8000000ULL) << 10) |
((field64 & 0xF80000ULL) << 13) | ((field64 & 0xF800ULL) << 15) | ((field64 & 0xF8ULL) << 18) |
((field32 & 0xF8000000ULL) >> 11) | ((field32 & 0xF80000ULL) >> 9) | ((field32 & 0xF800ULL) >> 6) | ((field32 & 0xF8ULL) >> 3);
field64 = *((PNGU_u64 *)(ctx->row_pointers[y*4+3]+x*12));
field32 = (PNGU_u64) *((PNGU_u32 *)(ctx->row_pointers[y*4+3]+x*12+8));
((PNGU_u64 *) buffer)[blockbase+3] =
alphaMask | ((field64 & 0xF800000000000000ULL) >> 1) | ((field64 & 0xF8000000000000ULL) << 2) |
((field64 & 0xF80000000000ULL) << 5) | ((field64 & 0xF800000000ULL) << 7) | ((field64 & 0xF8000000ULL) << 10) |
((field64 & 0xF80000ULL) << 13) | ((field64 & 0xF800ULL) << 15) | ((field64 & 0xF8ULL) << 18) |
((field32 & 0xF8000000ULL) >> 11) | ((field32 & 0xF80000ULL) >> 9) | ((field32 & 0xF800ULL) >> 6) | ((field32 & 0xF8ULL) >> 3);
}
}
else
{
// The user wants a translucid texture, so set MSB to 0 and encode colors in ARGB3444
default_alpha = (default_alpha << 4);
alphaMask = (((PNGU_u64) default_alpha) << 56) | (((PNGU_u64) default_alpha) << 40) |
(((PNGU_u64) default_alpha) << 24) | (((PNGU_u64) default_alpha) << 8);
for (y = 0; y < qheight; y++)
for (x = 0; x < qwidth; x++)
{
int blockbase = (y * qwidth + x) * 4;
PNGU_u64 field64 = *((PNGU_u64 *)(ctx->row_pointers[y*4]+x*12));
PNGU_u64 field32 = (PNGU_u64) *((PNGU_u32 *)(ctx->row_pointers[y*4]+x*12+8));
((PNGU_u64 *) buffer)[blockbase] =
alphaMask | ((field64 & 0xF000000000000000ULL) >> 4) | (field64 & 0xF0000000000000ULL) | ((field64 & 0xF00000000000ULL) << 4) |
((field64 & 0xF000000000ULL) << 4) | ((field64 & 0xF0000000ULL) << 8) | ((field64 & 0xF00000ULL) << 12) |
((field64 & 0xF000ULL) << 12) | ((field64 & 0xF0ULL) << 16) | ((field32 & 0xF0000000ULL) >> 12) |
((field32 & 0xF00000ULL) >> 12) | ((field32 & 0xF000ULL) >> 8) | ((field32 & 0xF0ULL) >> 4);
field64 = *((PNGU_u64 *)(ctx->row_pointers[y*4+1]+x*12));
field32 = (PNGU_u64) *((PNGU_u32 *)(ctx->row_pointers[y*4+1]+x*12+8));
((PNGU_u64 *) buffer)[blockbase+1] =
alphaMask | ((field64 & 0xF000000000000000ULL) >> 4) | (field64 & 0xF0000000000000ULL) | ((field64 & 0xF00000000000ULL) << 4) |
((field64 & 0xF000000000ULL) << 4) | ((field64 & 0xF0000000ULL) << 8) | ((field64 & 0xF00000ULL) << 12) |
((field64 & 0xF000ULL) << 12) | ((field64 & 0xF0ULL) << 16) | ((field32 & 0xF0000000ULL) >> 12) |
((field32 & 0xF00000ULL) >> 12) | ((field32 & 0xF000ULL) >> 8) | ((field32 & 0xF0ULL) >> 4);
field64 = *((PNGU_u64 *)(ctx->row_pointers[y*4+2]+x*12));
field32 = (PNGU_u64) *((PNGU_u32 *)(ctx->row_pointers[y*4+2]+x*12+8));
((PNGU_u64 *) buffer)[blockbase+2] =
alphaMask | ((field64 & 0xF000000000000000ULL) >> 4) | (field64 & 0xF0000000000000ULL) | ((field64 & 0xF00000000000ULL) << 4) |
((field64 & 0xF000000000ULL) << 4) | ((field64 & 0xF0000000ULL) << 8) | ((field64 & 0xF00000ULL) << 12) |
((field64 & 0xF000ULL) << 12) | ((field64 & 0xF0ULL) << 16) | ((field32 & 0xF0000000ULL) >> 12) |
((field32 & 0xF00000ULL) >> 12) | ((field32 & 0xF000ULL) >> 8) | ((field32 & 0xF0ULL) >> 4);
field64 = *((PNGU_u64 *)(ctx->row_pointers[y*4+3]+x*12));
field32 = (PNGU_u64) *((PNGU_u32 *)(ctx->row_pointers[y*4+3]+x*12+8));
((PNGU_u64 *) buffer)[blockbase+3] =
alphaMask | ((field64 & 0xF000000000000000ULL) >> 4) | (field64 & 0xF0000000000000ULL) | ((field64 & 0xF00000000000ULL) << 4) |
((field64 & 0xF000000000ULL) << 4) | ((field64 & 0xF0000000ULL) << 8) | ((field64 & 0xF00000ULL) << 12) |
((field64 & 0xF000ULL) << 12) | ((field64 & 0xF0ULL) << 16) | ((field32 & 0xF0000000ULL) >> 12) |
((field32 & 0xF00000ULL) >> 12) | ((field32 & 0xF000ULL) >> 8) | ((field32 & 0xF0ULL) >> 4);
}
}
}
// Free resources
free (ctx->img_data);
free (ctx->row_pointers);
// Success
return PNGU_OK;
}
int PNGU_DecodeTo4x4RGBA8 (IMGCTX ctx, PNGU_u32 width, PNGU_u32 height, void *buffer, PNGU_u8 default_alpha)
{
int result;
PNGU_u32 x, y, qwidth, qheight;
PNGU_u64 alphaMask;
// width and height need to be divisible by four
if ((width % 4) || (height % 4))
return PNGU_INVALID_WIDTH_OR_HEIGHT;
result = pngu_decode (ctx, width, height, 0);
if (result != PNGU_OK)
return result;
// Init some variables
qwidth = width / 4;
qheight = height / 4;
// Check is source image has an alpha channel
if ( (ctx->prop.imgColorType == PNGU_COLOR_TYPE_GRAY_ALPHA) || (ctx->prop.imgColorType == PNGU_COLOR_TYPE_RGB_ALPHA) )
{
// Alpha channel present, copy image to the output buffer
for (y = 0; y < qheight; y++)
for (x = 0; x < qwidth; x++)
{
int blockbase = (y * qwidth + x) * 8;
PNGU_u64 fieldA = *((PNGU_u64 *)(ctx->row_pointers[y*4]+x*16));
PNGU_u64 fieldB = *((PNGU_u64 *)(ctx->row_pointers[y*4]+x*16+8));
((PNGU_u64 *) buffer)[blockbase] =
((fieldA & 0xFF00000000ULL) << 24) | ((fieldA & 0xFF00000000000000ULL) >> 8) |
((fieldA & 0xFFULL) << 40) | ((fieldA & 0xFF000000ULL) << 8) |
((fieldB & 0xFF00000000ULL) >> 8) | ((fieldB & 0xFF00000000000000ULL) >> 40) |
((fieldB & 0xFFULL) << 8) | ((fieldB & 0xFF000000ULL) >> 24);
((PNGU_u64 *) buffer)[blockbase+4] =
((fieldA & 0xFFFF0000000000ULL) << 8) | ((fieldA & 0xFFFF00ULL) << 24) |
((fieldB & 0xFFFF0000000000ULL) >> 24) | ((fieldB & 0xFFFF00ULL) >> 8);
fieldA = *((PNGU_u64 *)(ctx->row_pointers[y*4+1]+x*16));
fieldB = *((PNGU_u64 *)(ctx->row_pointers[y*4+1]+x*16+8));
((PNGU_u64 *) buffer)[blockbase+1] =
((fieldA & 0xFF00000000ULL) << 24) | ((fieldA & 0xFF00000000000000ULL) >> 8) |
((fieldA & 0xFFULL) << 40) | ((fieldA & 0xFF000000ULL) << 8) |
((fieldB & 0xFF00000000ULL) >> 8) | ((fieldB & 0xFF00000000000000ULL) >> 40) |
((fieldB & 0xFFULL) << 8) | ((fieldB & 0xFF000000ULL) >> 24);
((PNGU_u64 *) buffer)[blockbase+5] =
((fieldA & 0xFFFF0000000000ULL) << 8) | ((fieldA & 0xFFFF00ULL) << 24) |
((fieldB & 0xFFFF0000000000ULL) >> 24) | ((fieldB & 0xFFFF00ULL) >> 8);
fieldA = *((PNGU_u64 *)(ctx->row_pointers[y*4+2]+x*16));
fieldB = *((PNGU_u64 *)(ctx->row_pointers[y*4+2]+x*16+8));
((PNGU_u64 *) buffer)[blockbase+2] =
((fieldA & 0xFF00000000ULL) << 24) | ((fieldA & 0xFF00000000000000ULL) >> 8) |
((fieldA & 0xFFULL) << 40) | ((fieldA & 0xFF000000ULL) << 8) |
((fieldB & 0xFF00000000ULL) >> 8) | ((fieldB & 0xFF00000000000000ULL) >> 40) |
((fieldB & 0xFFULL) << 8) | ((fieldB & 0xFF000000ULL) >> 24);
((PNGU_u64 *) buffer)[blockbase+6] =
((fieldA & 0xFFFF0000000000ULL) << 8) | ((fieldA & 0xFFFF00ULL) << 24) |
((fieldB & 0xFFFF0000000000ULL) >> 24) | ((fieldB & 0xFFFF00ULL) >> 8);
fieldA = *((PNGU_u64 *)(ctx->row_pointers[y*4+3]+x*16));
fieldB = *((PNGU_u64 *)(ctx->row_pointers[y*4+3]+x*16+8));
((PNGU_u64 *) buffer)[blockbase+3] =
((fieldA & 0xFF00000000ULL) << 24) | ((fieldA & 0xFF00000000000000ULL) >> 8) |
((fieldA & 0xFFULL) << 40) | ((fieldA & 0xFF000000ULL) << 8) |
((fieldB & 0xFF00000000ULL) >> 8) | ((fieldB & 0xFF00000000000000ULL) >> 40) |
((fieldB & 0xFFULL) << 8) | ((fieldB & 0xFF000000ULL) >> 24);
((PNGU_u64 *) buffer)[blockbase+7] =
((fieldA & 0xFFFF0000000000ULL) << 8) | ((fieldA & 0xFFFF00ULL) << 24) |
((fieldB & 0xFFFF0000000000ULL) >> 24) | ((fieldB & 0xFFFF00ULL) >> 8);
}
}
else
{
// No alpha channel present, copy image to the output buffer
alphaMask = (((PNGU_u64)default_alpha) << 56) | (((PNGU_u64)default_alpha) << 40) |
(((PNGU_u64)default_alpha) << 24) | (((PNGU_u64)default_alpha) << 8);
for (y = 0; y < qheight; y++)
for (x = 0; x < qwidth; x++)
{
int blockbase = (y * qwidth + x) * 8;
PNGU_u64 field64 = *((PNGU_u64 *)(ctx->row_pointers[y*4]+x*12));
PNGU_u64 field32 = (PNGU_u64) *((PNGU_u32 *)(ctx->row_pointers[y*4]+x*12+8));
((PNGU_u64 *) buffer)[blockbase] =
(((field64 & 0xFF00000000000000ULL) >> 8) | (field64 & 0xFF00000000ULL) |
((field64 & 0xFF00ULL) << 8) | ((field32 & 0xFF0000ULL) >> 16) | alphaMask);
((PNGU_u64 *) buffer)[blockbase+4] =
(((field64 & 0xFFFF0000000000ULL) << 8) | ((field64 & 0xFFFF0000ULL) << 16) |
((field64 & 0xFFULL) << 24) | ((field32 & 0xFF000000ULL) >> 8) | (field32 & 0xFFFFULL));
field64 = *((PNGU_u64 *)(ctx->row_pointers[y*4+1]+x*12));
field32 = (PNGU_u64) *((PNGU_u32 *)(ctx->row_pointers[y*4+1]+x*12+8));
((PNGU_u64 *) buffer)[blockbase+1] =
(((field64 & 0xFF00000000000000ULL) >> 8) | (field64 & 0xFF00000000ULL) |
((field64 & 0xFF00ULL) << 8) | ((field32 & 0xFF0000ULL) >> 16) | alphaMask);
((PNGU_u64 *) buffer)[blockbase+5] =
(((field64 & 0xFFFF0000000000ULL) << 8) | ((field64 & 0xFFFF0000ULL) << 16) |
((field64 & 0xFFULL) << 24) | ((field32 & 0xFF000000ULL) >> 8) | (field32 & 0xFFFFULL));
field64 = *((PNGU_u64 *)(ctx->row_pointers[y*4+2]+x*12));
field32 = (PNGU_u64) *((PNGU_u32 *)(ctx->row_pointers[y*4+2]+x*12+8));
((PNGU_u64 *) buffer)[blockbase+2] =
(((field64 & 0xFF00000000000000ULL) >> 8) | (field64 & 0xFF00000000ULL) |
((field64 & 0xFF00ULL) << 8) | ((field32 & 0xFF0000ULL) >> 16) | alphaMask);
((PNGU_u64 *) buffer)[blockbase+6] =
(((field64 & 0xFFFF0000000000ULL) << 8) | ((field64 & 0xFFFF0000ULL) << 16) |
((field64 & 0xFFULL) << 24) | ((field32 & 0xFF000000ULL) >> 8) | (field32 & 0xFFFFULL));
field64 = *((PNGU_u64 *)(ctx->row_pointers[y*4+3]+x*12));
field32 = (PNGU_u64) *((PNGU_u32 *)(ctx->row_pointers[y*4+3]+x*12+8));
((PNGU_u64 *) buffer)[blockbase+3] =
(((field64 & 0xFF00000000000000ULL) >> 8) | (field64 & 0xFF00000000ULL) |
((field64 & 0xFF00ULL) << 8) | ((field32 & 0xFF0000ULL) >> 16) | alphaMask);
((PNGU_u64 *) buffer)[blockbase+7] =
(((field64 & 0xFFFF0000000000ULL) << 8) | ((field64 & 0xFFFF0000ULL) << 16) |
((field64 & 0xFFULL) << 24) | ((field32 & 0xFF000000ULL) >> 8) | (field32 & 0xFFFFULL));
}
}
// Free resources
free (ctx->img_data);
free (ctx->row_pointers);
// Success
return PNGU_OK;
}
int PNGU_EncodeFromYCbYCr (IMGCTX ctx, PNGU_u32 width, PNGU_u32 height, void *buffer, PNGU_u32 stride)
{
png_uint_32 rowbytes;
PNGU_u32 x, y, buffWidth;
// Erase from the context any readed info
pngu_free_info (ctx);
ctx->propRead = 0;
// Check if the user has selected a file to write the image
if (ctx->source == PNGU_SOURCE_BUFFER);
else if (ctx->source == PNGU_SOURCE_DEVICE)
{
// Open file
if (!(ctx->fd = fopen (ctx->filename, "wb")))
return PNGU_CANT_OPEN_FILE;
}
else
return PNGU_NO_FILE_SELECTED;
// Allocation of libpng structs
ctx->png_ptr = png_create_write_struct (PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!(ctx->png_ptr))
{
if (ctx->source == PNGU_SOURCE_DEVICE)
fclose (ctx->fd);
return PNGU_LIB_ERROR;
}
ctx->info_ptr = png_create_info_struct (ctx->png_ptr);
if (!(ctx->info_ptr))
{
png_destroy_write_struct (&(ctx->png_ptr), (png_infopp)NULL);
if (ctx->source == PNGU_SOURCE_DEVICE)
fclose (ctx->fd);
return PNGU_LIB_ERROR;
}
if (ctx->source == PNGU_SOURCE_BUFFER)
{
// Installation of our custom data writer function
ctx->cursor = 0;
png_set_write_fn (ctx->png_ptr, ctx, pngu_write_data_to_buffer, pngu_flush_data_to_buffer);
}
else if (ctx->source == PNGU_SOURCE_DEVICE)
{
// Default data writer uses function fwrite, so it needs to use our FILE*
png_init_io (ctx->png_ptr, ctx->fd);
}
// Setup output file properties
png_set_IHDR (ctx->png_ptr, ctx->info_ptr, width, height, 8, PNG_COLOR_TYPE_RGB,
PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
// Allocate memory to store the image in RGB format
rowbytes = width * 3;
if (rowbytes % 4)
rowbytes = ((rowbytes / 4) + 1) * 4; // Add extra padding so each row starts in a 4 byte boundary
ctx->img_data = malloc (rowbytes * height);
if (!ctx->img_data)
{
png_destroy_write_struct (&(ctx->png_ptr), (png_infopp)NULL);
if (ctx->source == PNGU_SOURCE_DEVICE)
fclose (ctx->fd);
return PNGU_LIB_ERROR;
}
ctx->row_pointers = malloc (sizeof (png_bytep) * height);
if (!ctx->row_pointers)
{
png_destroy_write_struct (&(ctx->png_ptr), (png_infopp)NULL);
if (ctx->source == PNGU_SOURCE_DEVICE)
fclose (ctx->fd);
return PNGU_LIB_ERROR;
}
// Encode YCbYCr image into RGB8 format
buffWidth = (width + stride) / 2;
for (y = 0; y < height; y++)
{
ctx->row_pointers[y] = ctx->img_data + (y * rowbytes);
for (x = 0; x < (width / 2); x++)
PNGU_YCbYCr_TO_RGB8 ( ((PNGU_u32 *)buffer)[y*buffWidth+x],
((PNGU_u8 *) ctx->row_pointers[y]+x*6), ((PNGU_u8 *) ctx->row_pointers[y]+x*6+1),
((PNGU_u8 *) ctx->row_pointers[y]+x*6+2), ((PNGU_u8 *) ctx->row_pointers[y]+x*6+3),
((PNGU_u8 *) ctx->row_pointers[y]+x*6+4), ((PNGU_u8 *) ctx->row_pointers[y]+x*6+5) );
}
// Tell libpng where is our image data
png_set_rows (ctx->png_ptr, ctx->info_ptr, ctx->row_pointers);
// Write file header and image data
png_write_png (ctx->png_ptr, ctx->info_ptr, PNG_TRANSFORM_IDENTITY, NULL);
// Tell libpng we have no more data to write
png_write_end (ctx->png_ptr, (png_infop) NULL);
// Free resources
free (ctx->img_data);
free (ctx->row_pointers);
png_destroy_write_struct (&(ctx->png_ptr), &(ctx->info_ptr));
if (ctx->source == PNGU_SOURCE_DEVICE)
fclose (ctx->fd);
// Success
return PNGU_OK;
}
// This function is taken from a libogc example
PNGU_u32 PNGU_RGB8_TO_YCbYCr (PNGU_u8 r1, PNGU_u8 g1, PNGU_u8 b1, PNGU_u8 r2, PNGU_u8 g2, PNGU_u8 b2)
{
int y1, cb1, cr1, y2, cb2, cr2, cb, cr;
y1 = (299 * r1 + 587 * g1 + 114 * b1) / 1000;
cb1 = (-16874 * r1 - 33126 * g1 + 50000 * b1 + 12800000) / 100000;
cr1 = (50000 * r1 - 41869 * g1 - 8131 * b1 + 12800000) / 100000;
y2 = (299 * r2 + 587 * g2 + 114 * b2) / 1000;
cb2 = (-16874 * r2 - 33126 * g2 + 50000 * b2 + 12800000) / 100000;
cr2 = (50000 * r2 - 41869 * g2 - 8131 * b2 + 12800000) / 100000;
cb = (cb1 + cb2) >> 1;
cr = (cr1 + cr2) >> 1;
return (PNGU_u32) ((y1 << 24) | (cb << 16) | (y2 << 8) | cr);
}
void PNGU_YCbYCr_TO_RGB8 (PNGU_u32 ycbycr, PNGU_u8 *r1, PNGU_u8 *g1, PNGU_u8 *b1, PNGU_u8 *r2, PNGU_u8 *g2, PNGU_u8 *b2)
{
PNGU_u8 *val = (PNGU_u8 *) &ycbycr;
int r, g, b;
r = 1.371f * (val[3] - 128);
g = - 0.698f * (val[3] - 128) - 0.336f * (val[1] - 128);
b = 1.732f * (val[1] - 128);
*r1 = pngu_clamp (val[0] + r, 0, 255);
*g1 = pngu_clamp (val[0] + g, 0, 255);
*b1 = pngu_clamp (val[0] + b, 0, 255);
*r2 = pngu_clamp (val[2] + r, 0, 255);
*g2 = pngu_clamp (val[2] + g, 0, 255);
*b2 = pngu_clamp (val[2] + b, 0, 255);
}
int pngu_info (IMGCTX ctx)
{
png_byte magic[8];
png_uint_32 width;
png_uint_32 height;
png_color_16p background;
png_bytep trans;
png_color_16p trans_values;
int scale, i;
// Check if there is a file selected and if it is a valid .png
if (ctx->source == PNGU_SOURCE_BUFFER)
memcpy (magic, ctx->buffer, 8);
else if (ctx->source == PNGU_SOURCE_DEVICE)
{
// Open file
if (!(ctx->fd = fopen (ctx->filename, "rb")))
return PNGU_CANT_OPEN_FILE;
// Load first 8 bytes into magic buffer
if (fread (magic, 1, 8, ctx->fd) != 8)
{
fclose (ctx->fd);
return PNGU_CANT_READ_FILE;
}
}
else
return PNGU_NO_FILE_SELECTED;;
if (png_sig_cmp(magic, 0, 8) != 0)
{
if (ctx->source == PNGU_SOURCE_DEVICE)
fclose (ctx->fd);
return PNGU_FILE_IS_NOT_PNG;
}
// Allocation of libpng structs
ctx->png_ptr = png_create_read_struct (PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!(ctx->png_ptr))
{
if (ctx->source == PNGU_SOURCE_DEVICE)
fclose (ctx->fd);
return PNGU_LIB_ERROR;
}
ctx->info_ptr = png_create_info_struct (ctx->png_ptr);
if (!(ctx->info_ptr))
{
if (ctx->source == PNGU_SOURCE_DEVICE)
fclose (ctx->fd);
png_destroy_read_struct (&(ctx->png_ptr), (png_infopp)NULL, (png_infopp)NULL);
return PNGU_LIB_ERROR;
}
if (ctx->source == PNGU_SOURCE_BUFFER)
{
// Installation of our custom data provider function
ctx->cursor = 0;
png_set_read_fn (ctx->png_ptr, ctx, pngu_read_data_from_buffer);
}
else if (ctx->source == PNGU_SOURCE_DEVICE)
{
// Default data provider uses function fread, so it needs to use our FILE*
png_init_io (ctx->png_ptr, ctx->fd);
png_set_sig_bytes (ctx->png_ptr, 8); // We have read 8 bytes already to check PNG authenticity
}
// Read png header
png_read_info (ctx->png_ptr, ctx->info_ptr);
// Query image properties if they have not been queried before
if (!ctx->propRead)
{
png_get_IHDR(ctx->png_ptr, ctx->info_ptr, &width, &height,
(int *) &(ctx->prop.imgBitDepth),
(int *) &(ctx->prop.imgColorType),
NULL, NULL, NULL);
ctx->prop.imgWidth = width;
ctx->prop.imgHeight = height;
switch (ctx->prop.imgColorType)
{
case PNG_COLOR_TYPE_GRAY:
ctx->prop.imgColorType = PNGU_COLOR_TYPE_GRAY;
break;
case PNG_COLOR_TYPE_GRAY_ALPHA:
ctx->prop.imgColorType = PNGU_COLOR_TYPE_GRAY_ALPHA;
break;
case PNG_COLOR_TYPE_PALETTE:
ctx->prop.imgColorType = PNGU_COLOR_TYPE_PALETTE;
break;
case PNG_COLOR_TYPE_RGB:
ctx->prop.imgColorType = PNGU_COLOR_TYPE_RGB;
break;
case PNG_COLOR_TYPE_RGB_ALPHA:
ctx->prop.imgColorType = PNGU_COLOR_TYPE_RGB_ALPHA;
break;
default:
ctx->prop.imgColorType = PNGU_COLOR_TYPE_UNKNOWN;
break;
}
// Constant used to scale 16 bit values to 8 bit values
scale = 1;
if (ctx->prop.imgBitDepth == 16)
scale = 256;
// Query background color, if any.
ctx->prop.validBckgrnd = 0;
if (((ctx->prop.imgColorType == PNGU_COLOR_TYPE_RGB) || (ctx->prop.imgColorType == PNGU_COLOR_TYPE_RGB_ALPHA)) &&
(png_get_bKGD (ctx->png_ptr, ctx->info_ptr, &background)))
{
ctx->prop.validBckgrnd = 1;
ctx->prop.bckgrnd.r = background->red / scale;
ctx->prop.bckgrnd.g = background->green / scale;
ctx->prop.bckgrnd.b = background->blue / scale;
}
else if (((ctx->prop.imgColorType == PNGU_COLOR_TYPE_GRAY) || (ctx->prop.imgColorType == PNGU_COLOR_TYPE_GRAY_ALPHA)) &&
(png_get_bKGD (ctx->png_ptr, ctx->info_ptr, &background)))
{
ctx->prop.validBckgrnd = 1;
ctx->prop.bckgrnd.r = ctx->prop.bckgrnd.g = ctx->prop.bckgrnd.b = background->gray / scale;
}
// Query list of transparent colors, if any.
ctx->prop.numTrans = 0;
ctx->prop.trans = NULL;
if (((ctx->prop.imgColorType == PNGU_COLOR_TYPE_RGB) || (ctx->prop.imgColorType == PNGU_COLOR_TYPE_RGB_ALPHA)) &&
(png_get_tRNS (ctx->png_ptr, ctx->info_ptr, &trans, (int *) &(ctx->prop.numTrans), &trans_values)))
{
if (ctx->prop.numTrans)
{
ctx->prop.trans = malloc (sizeof (PNGUCOLOR) * ctx->prop.numTrans);
if (ctx->prop.trans)
for (i = 0; i < ctx->prop.numTrans; i++)
{
ctx->prop.trans[i].r = trans_values[i].red / scale;
ctx->prop.trans[i].g = trans_values[i].green / scale;
ctx->prop.trans[i].b = trans_values[i].blue / scale;
}
else
ctx->prop.numTrans = 0;
}
}
else if (((ctx->prop.imgColorType == PNGU_COLOR_TYPE_GRAY) || (ctx->prop.imgColorType == PNGU_COLOR_TYPE_GRAY_ALPHA)) &&
(png_get_tRNS (ctx->png_ptr, ctx->info_ptr, &trans, (int *) &(ctx->prop.numTrans), &trans_values)))
{
if (ctx->prop.numTrans)
{
ctx->prop.trans = malloc (sizeof (PNGUCOLOR) * ctx->prop.numTrans);
if (ctx->prop.trans)
for (i = 0; i < ctx->prop.numTrans; i++)
ctx->prop.trans[i].r = ctx->prop.trans[i].g = ctx->prop.trans[i].b =
trans_values[i].gray / scale;
else
ctx->prop.numTrans = 0;
}
}
ctx->propRead = 1;
}
// Success
ctx->infoRead = 1;
return PNGU_OK;
}
int pngu_decode (IMGCTX ctx, PNGU_u32 width, PNGU_u32 height, PNGU_u32 stripAlpha)
{
png_uint_32 rowbytes;
int i;
// Read info if it hasn't been read before
if (!ctx->infoRead)
{
i = pngu_info (ctx);
if (i != PNGU_OK)
return i;
}
// Check if the user has specified the real width and height of the image
if ( (ctx->prop.imgWidth != width) || (ctx->prop.imgHeight != height) )
return PNGU_INVALID_WIDTH_OR_HEIGHT;
// Check if color type is supported by PNGU
if ( (ctx->prop.imgColorType == PNGU_COLOR_TYPE_PALETTE) || (ctx->prop.imgColorType == PNGU_COLOR_TYPE_UNKNOWN) )
return PNGU_UNSUPPORTED_COLOR_TYPE;
// Scale 16 bit samples to 8 bit
if (ctx->prop.imgBitDepth == 16)
png_set_strip_16 (ctx->png_ptr);
// Remove alpha channel if we don't need it
if (stripAlpha && ((ctx->prop.imgColorType == PNGU_COLOR_TYPE_RGB_ALPHA) || (ctx->prop.imgColorType == PNGU_COLOR_TYPE_GRAY_ALPHA)))
png_set_strip_alpha (ctx->png_ptr);
// Expand 1, 2 and 4 bit samples to 8 bit
if (ctx->prop.imgBitDepth < 8)
png_set_packing (ctx->png_ptr);
// Transform grayscale images to RGB
if ( (ctx->prop.imgColorType == PNGU_COLOR_TYPE_GRAY) || (ctx->prop.imgColorType == PNGU_COLOR_TYPE_GRAY_ALPHA) )
png_set_gray_to_rgb (ctx->png_ptr);
// Flush transformations
png_read_update_info (ctx->png_ptr, ctx->info_ptr);
// Allocate memory to store the image
rowbytes = png_get_rowbytes (ctx->png_ptr, ctx->info_ptr);
if (rowbytes % 4)
rowbytes = ((rowbytes / 4) + 1) * 4; // Add extra padding so each row starts in a 4 byte boundary
ctx->img_data = malloc (rowbytes * ctx->prop.imgHeight);
if (!ctx->img_data)
{
pngu_free_info (ctx);
return PNGU_LIB_ERROR;
}
ctx->row_pointers = malloc (sizeof (png_bytep) * ctx->prop.imgHeight);
if (!ctx->row_pointers)
{
free (ctx->img_data);
pngu_free_info (ctx);
return PNGU_LIB_ERROR;
}
for (i = 0; i < ctx->prop.imgHeight; i++)
ctx->row_pointers[i] = ctx->img_data + (i * rowbytes);
// Transform the image and copy it to our allocated memory
png_read_image (ctx->png_ptr, ctx->row_pointers);
// Free resources
pngu_free_info (ctx);
// Success
return PNGU_OK;
}
void pngu_free_info (IMGCTX ctx)
{
if (ctx->infoRead)
{
if (ctx->source == PNGU_SOURCE_DEVICE)
fclose (ctx->fd);
png_destroy_read_struct (&(ctx->png_ptr), &(ctx->info_ptr), (png_infopp)NULL);
ctx->infoRead = 0;
}
}
// Custom data provider function used for reading from memory buffers.
void pngu_read_data_from_buffer (png_structp png_ptr, png_bytep data, png_size_t length)
{
IMGCTX ctx = (IMGCTX) png_get_io_ptr (png_ptr);
memcpy (data, ctx->buffer + ctx->cursor, length);
ctx->cursor += length;
}
// Custom data writer function used for writing to memory buffers.
void pngu_write_data_to_buffer (png_structp png_ptr, png_bytep data, png_size_t length)
{
IMGCTX ctx = (IMGCTX) png_get_io_ptr (png_ptr);
memcpy (ctx->buffer + ctx->cursor, data, length);
ctx->cursor += length;
}
// Custom data flusher function used for writing to memory buffers.
void pngu_flush_data_to_buffer (png_structp png_ptr)
{
// Nothing to do here
}
// Function used in YCbYCr to RGB decoding
int pngu_clamp (int value, int min, int max)
{
if (value < min)
value = min;
else if (value > max)
value = max;
return value;
}
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