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|
/*
* png.c --
*
* PNG photo image type, Tcl/Tk package
*
* Copyright (c) 2002 Andreas Kupries <andreas_kupries@users.sourceforge.net>
*
* This Tk image format handler reads and writes PNG files in the standard
* PNG file format. ("PNG" should be the format name.) It can also read
* and write strings containing base64-encoded PNG data.
*
* Author : Jan Nijtmans
* Date : 2/13/97
* Original implementation : Joel Crisp
*
* The following format options are available:
*
* Read PNG image: "png -verbose <bool> -gamma <float> -matte <bool> -alpha <float>"
* Write PNG image: None yet.
*
* -verbose <bool>: If set to true, additional information about the file
* format is printed to stdout. Default is "false".
* -gamma <float>: Use the specified gamma value when reading an image.
* This option overwrites gamma values specified in the file.
* If this option is not specified and no gamma value is in the file,
* a default value of 1.0 is used.
* -matte <bool>: If set to false, a matte (alpha) channel is ignored
* during reading. Default is true.
* -alpha <float>: An additional alpha filtering for the overall image, which
* allows the background on which the image is displayed to show through.
* This usually also has the effect of desaturating the image.
* The alphaValue must be between 0.0 and 1.0.
* Specifying an alpha value, overrides the setting of the matte flag,
* i.e. reading a file which has no alpha channel (Greyscale, RGB) will
* add an alpha channel to the image independent of the matte flag setting.
*/
/*
* Generic initialization code, parameterized via CPACKAGE and PACKAGE.
*/
#include "pngtcl.h"
#include <string.h>
#include <stdlib.h>
static int SetupPngLibrary(Tcl_Interp *interp);
#define MORE_INITIALIZATION \
if (SetupPngLibrary (interp) != TCL_OK) { return TCL_ERROR; }
#include "init.c"
#define COMPRESS_THRESHOLD 1024
typedef struct png_text_struct_compat
{
png_text compat;
png_size_t itxt_length; /* length of the itxt string */
png_charp lang; /* language code, 0-79 characters
or a NULL pointer */
png_charp lang_key; /* keyword translated UTF-8 string, 0 or more
chars or a NULL pointer */
} png_text_compat;
typedef struct cleanup_info {
Tcl_Interp *interp;
jmp_buf jmpbuf;
} cleanup_info;
typedef struct {
int verbose;
int matte;
float alpha;
float gamma;
} FMTOPT;
/*
* Prototypes for local procedures defined in this file:
*/
static int CommonMatchPNG(tkimg_MFile *handle, int *widthPtr,
int *heightPtr);
static int CommonReadPNG(png_structp png_ptr,
Tcl_Interp* interp, const char *fileName, Tcl_Obj *format,
Tk_PhotoHandle imageHandle, int destX, int destY, int width,
int height, int srcX, int srcY);
static int CommonWritePNG(Tcl_Interp *interp, png_structp png_ptr,
png_infop info_ptr, Tcl_Obj *format,
Tk_PhotoImageBlock *blockPtr);
static void tk_png_error(png_structp, png_const_charp);
static void tk_png_warning(png_structp, png_const_charp);
/*
* These functions are used for all Input/Output.
*/
static void tk_png_read(png_structp, png_bytep, png_size_t);
static void tk_png_write(png_structp, png_bytep, png_size_t);
static void tk_png_flush(png_structp);
#define OUT Tcl_WriteChars (outChan, str, -1)
static void PrintReadInfo (int width, int height, int nchans, int bits,
double fileGamma, const char *filename, const char *msg)
{
Tcl_Channel outChan;
char str[256];
outChan = Tcl_GetStdChannel (TCL_STDOUT);
if (!outChan) {
return;
}
sprintf(str, "%s %s\n", msg, filename); OUT;
sprintf(str, "\tSize in pixel : %d x %d\n", width, height); OUT;
sprintf(str, "\tNum channels : %d\n", nchans); OUT;
sprintf(str, "\tBits per channel: %d\n", bits); OUT;
if (fileGamma < 0.0) {
sprintf(str, "\tFile gamma : %s\n", "None"); OUT;
} else {
sprintf(str, "\tFile gamma : %f\n", fileGamma); OUT;
}
Tcl_Flush(outChan);
}
#undef OUT
static int ParseFormatOpts (interp, format, opts)
Tcl_Interp *interp;
Tcl_Obj *format;
FMTOPT *opts;
{
static const char *const pngOptions[] = {
"-matte", "-alpha", "-gamma", "-verbose", NULL
};
int objc, i, index;
char *optionStr;
Tcl_Obj **objv;
int boolVal;
double doubleVal;
opts->matte = 1;
opts->alpha = -1.0;
opts->gamma = 1.0;
opts->verbose = 0;
if (tkimg_ListObjGetElements(interp, format, &objc, &objv) != TCL_OK) {
return TCL_ERROR;
}
if (objc) {
for (i=1; i<objc; i++) {
if (Tcl_GetIndexFromObj(interp, objv[i], (const char *CONST86 *)pngOptions,
"format option", 0, &index) != TCL_OK) {
return TCL_ERROR;
}
if (++i >= objc) {
Tcl_AppendResult(interp, "No value for option \"",
Tcl_GetStringFromObj (objv[--i], (int *) NULL),
"\"", (char *) NULL);
return TCL_ERROR;
}
optionStr = Tcl_GetStringFromObj(objv[i], (int *) NULL);
switch(index) {
case 0:
if (Tcl_GetBoolean(interp, optionStr, &boolVal) == TCL_ERROR) {
Tcl_AppendResult (interp, "Invalid matte mode \"", optionStr,
"\": should be 1 or 0, on or off, true or false",
(char *) NULL);
return TCL_ERROR;
}
opts->matte = boolVal;
break;
case 1:
if (Tcl_GetDouble(interp, optionStr, &doubleVal) == TCL_ERROR) {
Tcl_AppendResult (interp, "Invalid alpha value \"", optionStr,
"\": Must be greater than or equal to zero.", (char *) NULL);
return TCL_ERROR;
}
opts->alpha = doubleVal;
if (opts->alpha < 0.0 ) opts->alpha = 0.0;
if (opts->alpha > 1.0 ) opts->alpha = 1.0;
break;
case 2:
if (Tcl_GetDouble(interp, optionStr, &doubleVal) == TCL_ERROR) {
Tcl_AppendResult (interp, "Invalid gamma value \"", optionStr,
"\": Must be greater than or equal to zero.", (char *) NULL);
return TCL_ERROR;
}
if (doubleVal >= 0.0) {
opts->gamma = doubleVal;
}
break;
case 3:
if (Tcl_GetBoolean(interp, optionStr, &boolVal) == TCL_ERROR) {
Tcl_AppendResult (interp, "Invalid verbose mode \"", optionStr,
"\": should be 1 or 0, on or off, true or false",
(char *) NULL);
return TCL_ERROR;
}
opts->verbose = boolVal;
break;
}
}
}
return TCL_OK;
}
/*
*
*/
static int
SetupPngLibrary (interp)
Tcl_Interp *interp;
{
if (Pngtcl_InitStubs(interp, PNGTCL_VERSION, 0) == NULL) {
return TCL_ERROR;
}
return TCL_OK;
}
static void
tk_png_error(png_ptr, error_msg)
png_structp png_ptr;
png_const_charp error_msg;
{
cleanup_info *info = (cleanup_info *) png_get_error_ptr(png_ptr);
Tcl_AppendResult(info->interp, error_msg, (char *) NULL);
longjmp(info->jmpbuf,1);
}
static void
tk_png_warning(png_ptr, error_msg)
png_structp png_ptr;
png_const_charp error_msg;
{
return;
}
static void
tk_png_read(png_ptr, data, length)
png_structp png_ptr;
png_bytep data;
png_size_t length;
{
if (tkimg_Read2((tkimg_MFile *) png_get_progressive_ptr(png_ptr),
(char *) data, (size_t) length) != (int) length) {
png_error(png_ptr, "Read Error");
}
}
static void
tk_png_write(png_ptr, data, length)
png_structp png_ptr;
png_bytep data;
png_size_t length;
{
if (tkimg_Write2((tkimg_MFile *) png_get_progressive_ptr(png_ptr),
(char *) data, (size_t) length) != (int) length) {
png_error(png_ptr, "Write Error");
}
}
static void
tk_png_flush(png_ptr)
png_structp png_ptr;
{
}
static int ChnMatch(
Tcl_Channel chan,
const char *fileName,
Tcl_Obj *format,
int *widthPtr,
int *heightPtr,
Tcl_Interp *interp
) {
tkimg_MFile handle;
handle.data = (char *) chan;
handle.state = IMG_CHAN;
return CommonMatchPNG(&handle, widthPtr, heightPtr);
}
static int
ObjMatch(
Tcl_Obj *data,
Tcl_Obj *format,
int *widthPtr,
int *heightPtr,
Tcl_Interp *interp
) {
tkimg_MFile handle;
if (!tkimg_ReadInit(data, '\211', &handle)) {
return 0;
}
return CommonMatchPNG(&handle, widthPtr, heightPtr);
}
static int
CommonMatchPNG(handle, widthPtr, heightPtr)
tkimg_MFile *handle;
int *widthPtr, *heightPtr;
{
unsigned char buf[8];
if ((tkimg_Read2(handle, (char *) buf, 8) != 8)
|| (strncmp("\211\120\116\107\15\12\32\12", (char *) buf, 8) != 0)
|| (tkimg_Read2(handle, (char *) buf, 8) != 8)
|| (strncmp("\111\110\104\122", (char *) buf+4, 4) != 0)
|| (tkimg_Read2(handle, (char *) buf, 8) != 8)) {
return 0;
}
*widthPtr = (buf[0]<<24) + (buf[1]<<16) + (buf[2]<<8) + buf[3];
*heightPtr = (buf[4]<<24) + (buf[5]<<16) + (buf[6]<<8) + buf[7];
return 1;
}
static int
ChnRead(interp, chan, fileName, format, imageHandle,
destX, destY, width, height, srcX, srcY)
Tcl_Interp *interp;
Tcl_Channel chan;
const char *fileName;
Tcl_Obj *format;
Tk_PhotoHandle imageHandle;
int destX, destY;
int width, height;
int srcX, srcY;
{
png_structp png_ptr;
tkimg_MFile handle;
cleanup_info cleanup;
handle.data = (char *) chan;
handle.state = IMG_CHAN;
cleanup.interp = interp;
png_ptr=png_create_read_struct(PNG_LIBPNG_VER_STRING,
(png_voidp) &cleanup,tk_png_error,tk_png_warning);
if (!png_ptr) return(0);
png_set_read_fn(png_ptr, (png_voidp) &handle, tk_png_read);
return CommonReadPNG(png_ptr, interp, fileName, format, imageHandle, destX, destY,
width, height, srcX, srcY);
}
static int
ObjRead (interp, dataObj, format, imageHandle,
destX, destY, width, height, srcX, srcY)
Tcl_Interp *interp;
Tcl_Obj *dataObj;
Tcl_Obj *format;
Tk_PhotoHandle imageHandle;
int destX, destY;
int width, height;
int srcX, srcY;
{
png_structp png_ptr;
tkimg_MFile handle;
cleanup_info cleanup;
cleanup.interp = interp;
png_ptr=png_create_read_struct(PNG_LIBPNG_VER_STRING,
(png_voidp) &cleanup,tk_png_error,tk_png_warning);
if (!png_ptr) return TCL_ERROR;
tkimg_ReadInit(dataObj,'\211',&handle);
png_set_read_fn(png_ptr,(png_voidp) &handle, tk_png_read);
return CommonReadPNG(png_ptr, interp, "InlineData", format, imageHandle, destX, destY,
width, height, srcX, srcY);
}
static int
CommonReadPNG(png_ptr, interp, fileName, format, imageHandle, destX, destY,
width, height, srcX, srcY)
png_structp png_ptr;
Tcl_Interp *interp;
const char *fileName;
Tcl_Obj *format;
Tk_PhotoHandle imageHandle;
int destX, destY;
int width, height;
int srcX, srcY;
{
png_infop info_ptr;
png_infop end_info;
char **png_data = NULL;
Tk_PhotoImageBlock block;
unsigned int i;
png_uint_32 info_width, info_height;
int bit_depth, color_type, interlace_type;
int intent;
int result = TCL_OK;
double fileGamma = -1.0;
int useAlpha = 0;
int addAlpha = 0;
FMTOPT opts;
if (ParseFormatOpts(interp, format, &opts) != TCL_OK) {
return TCL_ERROR;
}
info_ptr=png_create_info_struct(png_ptr);
if (!info_ptr) {
png_destroy_read_struct(&png_ptr,NULL,NULL);
return(TCL_ERROR);
}
end_info=png_create_info_struct(png_ptr);
if (!end_info) {
png_destroy_read_struct(&png_ptr,&info_ptr,NULL);
return(TCL_ERROR);
}
if (setjmp((((cleanup_info *) png_get_error_ptr(png_ptr))->jmpbuf))) {
if (png_data) {
ckfree((char *)png_data);
}
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
return TCL_ERROR;
}
png_read_info(png_ptr,info_ptr);
png_get_IHDR(png_ptr, info_ptr, &info_width, &info_height, &bit_depth,
&color_type, &interlace_type, (int *) NULL, (int *) NULL);
if ((srcX + width) > (int) info_width) {
width = info_width - srcX;
}
if ((srcY + height) > (int) info_height) {
height = info_height - srcY;
}
if ((width <= 0) || (height <= 0)
|| (srcX >= (int) info_width)
|| (srcY >= (int) info_height)) {
png_destroy_read_struct(&png_ptr,&info_ptr,&end_info);
return TCL_OK;
}
if (tkimg_PhotoExpand(interp, imageHandle, destX + width, destY + height) == TCL_ERROR) {
png_destroy_read_struct(&png_ptr,&info_ptr,&end_info);
return TCL_ERROR;
}
Tk_PhotoGetImage(imageHandle, &block);
png_set_scale_16(png_ptr);
png_set_expand(png_ptr);
if (png_get_sRGB(png_ptr, info_ptr, &intent)) {
png_set_sRGB(png_ptr, info_ptr, intent);
} else {
if (opts.gamma < 0.0) {
/* No gamma specified on the command line.
* Check, if a gamma value is specified in the file.
*/
if (png_get_gAMA(png_ptr, info_ptr, &fileGamma)) {
png_set_gamma(png_ptr, 1.0, fileGamma);
}
} else {
png_set_gamma(png_ptr, 1.0, opts.gamma);
}
}
if ((color_type & PNG_COLOR_MASK_ALPHA)
|| png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
/* Image has an alpha channel.
Check, if we don't want to use the alpha channel (matte == false) */
if (!opts.matte) {
png_set_strip_alpha (png_ptr);
}
} else {
/* Image has no alpha channel.
If a valid alpha multiply has been specified, add an alpha channel to the image.
The matte flag is ignored. */
if (opts.alpha >= 0.0) {
png_set_add_alpha(png_ptr, (unsigned int)(opts.alpha*255), PNG_FILLER_AFTER);
}
}
if (opts.verbose) {
PrintReadInfo (info_width, info_height, png_get_channels(png_ptr, info_ptr),
bit_depth, fileGamma, fileName, "Reading image:");
}
/* Note: png_read_update_info may only be called once per info_ptr !! */
png_read_update_info(png_ptr, info_ptr);
block.pixelSize = png_get_channels(png_ptr, info_ptr);
block.pitch = png_get_rowbytes(png_ptr, info_ptr);
if ((color_type & PNG_COLOR_MASK_COLOR) == 0) {
/* grayscale image */
block.offset[1] = 0;
block.offset[2] = 0;
}
block.width = width;
block.height = height;
if ((color_type & PNG_COLOR_MASK_ALPHA)
|| png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
/* Image has an alpha channel.
Check, if we don't want to use the alpha channel (matte == false) */
if (!opts.matte) {
block.offset[3] = 0;
} else {
block.offset[3] = block.pixelSize - 1;
if ( opts.alpha >= 0.0) {
useAlpha = 1;
}
}
} else {
/* Image has no alpha channel.
If a valid alpha multiply has been specified, add an alpha channel to the image.
The matte flag is ignored. */
if ( opts.alpha >= 0.0) {
addAlpha = 1;
} else {
block.offset[3] = 0;
}
}
if (addAlpha) {
block.offset[3] = block.pixelSize - 1;
}
png_data = (char **) ckalloc(sizeof(char *) * info_height + info_height * block.pitch);
for(i=0;i<info_height;i++) {
png_data[i] = ((char *) png_data) + (sizeof(char *) * info_height + i * block.pitch);
}
png_read_image(png_ptr,(png_bytepp) png_data);
block.pixelPtr=(unsigned char *) (png_data[srcY]+srcX*block.pixelSize);
if (useAlpha) {
unsigned char * alphaPtr = block.pixelPtr + block.offset[3];
for(i=0; i<(unsigned int)(height*width); i++) {
*alphaPtr = opts.alpha * *alphaPtr;
alphaPtr += block.offset[3] + 1 ;
}
}
if (tkimg_PhotoPutBlock(
interp, imageHandle, &block,
destX, destY, width, height,
block.offset[3]? TK_PHOTO_COMPOSITE_OVERLAY: TK_PHOTO_COMPOSITE_SET) == TCL_ERROR) {
result = TCL_ERROR;
}
ckfree((char *) png_data);
png_destroy_read_struct(&png_ptr,&info_ptr,&end_info);
return result;
}
static int
ChnWrite (interp, filename, format, blockPtr)
Tcl_Interp *interp;
const char *filename;
Tcl_Obj *format;
Tk_PhotoImageBlock *blockPtr;
{
png_structp png_ptr;
png_infop info_ptr;
tkimg_MFile handle;
int result;
cleanup_info cleanup;
Tcl_Channel chan = (Tcl_Channel) NULL;
chan = tkimg_OpenFileChannel(interp, filename, 0644);
if (!chan) {
return TCL_ERROR;
}
handle.data = (char *) chan;
handle.state = IMG_CHAN;
cleanup.interp = interp;
png_ptr=png_create_write_struct(PNG_LIBPNG_VER_STRING,
(png_voidp) &cleanup,tk_png_error,tk_png_warning);
if (!png_ptr) {
Tcl_Close(NULL, chan);
return TCL_ERROR;
}
info_ptr=png_create_info_struct(png_ptr);
if (!info_ptr) {
png_destroy_write_struct(&png_ptr,NULL);
Tcl_Close(NULL, chan);
return TCL_ERROR;
}
png_set_write_fn(png_ptr,(png_voidp) &handle, tk_png_write, tk_png_flush);
result = CommonWritePNG(interp, png_ptr, info_ptr, format, blockPtr);
Tcl_Close(NULL, chan);
return result;
}
static int StringWrite(
Tcl_Interp *interp,
Tcl_Obj *format,
Tk_PhotoImageBlock *blockPtr
) {
png_structp png_ptr;
png_infop info_ptr;
tkimg_MFile handle;
int result;
cleanup_info cleanup;
Tcl_DString data;
Tcl_DStringInit(&data);
cleanup.interp = interp;
png_ptr=png_create_write_struct(PNG_LIBPNG_VER_STRING,
(png_voidp) &cleanup, tk_png_error, tk_png_warning);
if (!png_ptr) {
return TCL_ERROR;
}
info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr) {
png_destroy_write_struct(&png_ptr,NULL);
return TCL_ERROR;
}
png_set_write_fn(png_ptr, (png_voidp) &handle, tk_png_write, tk_png_flush);
tkimg_WriteInit(&data, &handle);
result = CommonWritePNG(interp, png_ptr, info_ptr, format, blockPtr);
tkimg_Putc(IMG_DONE, &handle);
if (result == TCL_OK) {
Tcl_DStringResult(interp, &data);
} else {
Tcl_DStringFree(&data);
}
return result;
}
static int
CommonWritePNG(interp, png_ptr, info_ptr, format, blockPtr)
Tcl_Interp *interp;
png_structp png_ptr;
png_infop info_ptr;
Tcl_Obj *format;
Tk_PhotoImageBlock *blockPtr;
{
int greenOffset, blueOffset, alphaOffset;
int tagcount = 0;
Tcl_Obj **tags = (Tcl_Obj **) NULL;
int I, pass, number_passes, color_type;
int newPixelSize;
png_bytep row_pointers = (png_bytep) NULL;
if (tkimg_ListObjGetElements(interp, format, &tagcount, &tags) != TCL_OK) {
return TCL_ERROR;
}
tagcount = (tagcount > 1) ? (tagcount - 1) / 2: 0;
if (setjmp((((cleanup_info *) png_get_error_ptr(png_ptr))->jmpbuf))) {
if (row_pointers) {
ckfree((char *) row_pointers);
}
png_destroy_write_struct(&png_ptr,&info_ptr);
return TCL_ERROR;
}
greenOffset = blockPtr->offset[1] - blockPtr->offset[0];
blueOffset = blockPtr->offset[2] - blockPtr->offset[0];
alphaOffset = blockPtr->offset[0];
if (alphaOffset < blockPtr->offset[2]) {
alphaOffset = blockPtr->offset[2];
}
if (++alphaOffset < blockPtr->pixelSize) {
alphaOffset -= blockPtr->offset[0];
} else {
alphaOffset = 0;
}
if (greenOffset || blueOffset) {
color_type = PNG_COLOR_TYPE_RGB;
newPixelSize = 3;
} else {
color_type = PNG_COLOR_TYPE_GRAY;
newPixelSize = 1;
}
if (alphaOffset) {
color_type |= PNG_COLOR_MASK_ALPHA;
newPixelSize++;
#if 0 /* The function png_set_filler doesn't seem to work; don't known why :-( */
} else if ((blockPtr->pixelSize==4) && (newPixelSize == 3)
&& (png_set_filler != NULL)) {
/*
* The set_filler() function doesn't need to be called
* because the code below can handle all necessary
* re-allocation of memory. Only it is more economically
* to let the PNG library do that, which is only
* possible with v0.95 and higher.
*/
png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
newPixelSize++;
#endif
}
png_set_IHDR(png_ptr, info_ptr, blockPtr->width, blockPtr->height, 8,
color_type, PNG_INTERLACE_ADAM7, PNG_COMPRESSION_TYPE_BASE,
PNG_FILTER_TYPE_BASE);
if (tagcount > 0) {
png_text_compat text;
for(I=0;I<tagcount;I++) {
int length;
memset(&text, 0, sizeof(png_text_compat));
text.compat.key = Tcl_GetStringFromObj(tags[2*I+1], (int *) NULL);
text.compat.text = Tcl_GetStringFromObj(tags[2*I+2], &length);
text.compat.text_length = length;
if (text.compat.text_length>COMPRESS_THRESHOLD) {
text.compat.compression = PNG_TEXT_COMPRESSION_zTXt;
} else {
text.compat.compression = PNG_TEXT_COMPRESSION_NONE;
}
png_set_text(png_ptr, info_ptr, &text.compat, 1);
}
}
png_write_info(png_ptr,info_ptr);
number_passes = png_set_interlace_handling(png_ptr);
if (blockPtr->pixelSize != newPixelSize) {
int J, oldPixelSize;
png_bytep src, dst;
oldPixelSize = blockPtr->pixelSize;
row_pointers = (png_bytep)
ckalloc(blockPtr->width * newPixelSize);
for (pass = 0; pass < number_passes; pass++) {
for(I=0; I<blockPtr->height; I++) {
src = (png_bytep) blockPtr->pixelPtr
+ I * blockPtr->pitch + blockPtr->offset[0];
dst = row_pointers;
for (J = blockPtr->width; J > 0; J--) {
memcpy(dst, src, newPixelSize);
src += oldPixelSize;
dst += newPixelSize;
}
png_write_row(png_ptr, row_pointers);
}
}
ckfree((char *) row_pointers);
row_pointers = NULL;
} else {
for (pass = 0; pass < number_passes; pass++) {
for(I=0;I<blockPtr->height;I++) {
png_write_row(png_ptr, (png_bytep) blockPtr->pixelPtr
+ I * blockPtr->pitch + blockPtr->offset[0]);
}
}
}
png_write_end(png_ptr,NULL);
png_destroy_write_struct(&png_ptr,&info_ptr);
return(TCL_OK);
}
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