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/*
* tkImgPPM.c --
*
* A photo image file handler for PPM (Portable PixMap) files.
*
* Copyright (c) 1994 The Australian National University.
* Copyright (c) 1994-1997 Sun Microsystems, Inc.
*
* See the file "license.terms" for information on usage and redistribution of
* this file, and for a DISCLAIMER OF ALL WARRANTIES.
*
* Author: Paul Mackerras (paulus@cs.anu.edu.au),
* Department of Computer Science,
* Australian National University.
*/
#include "tkInt.h"
/*
* The maximum amount of memory to allocate for data read from the file. If we
* need more than this, we do it in pieces.
*/
#define MAX_MEMORY 10000 /* don't allocate > 10KB */
/*
* Define PGM and PPM, i.e. gray images and color images.
*/
#define PGM 1
#define PPM 2
/*
* The format record for the PPM file format:
*/
static int FileMatchPPM(Tcl_Channel chan, const char *fileName,
Tcl_Obj *format, int *widthPtr, int *heightPtr,
Tcl_Interp *interp);
static int FileReadPPM(Tcl_Interp *interp, Tcl_Channel chan,
const char *fileName, Tcl_Obj *format,
Tk_PhotoHandle imageHandle, int destX, int destY,
int width, int height, int srcX, int srcY);
static int FileWritePPM(Tcl_Interp *interp, const char *fileName,
Tcl_Obj *format, Tk_PhotoImageBlock *blockPtr);
static int StringWritePPM(Tcl_Interp *interp, Tcl_Obj *format,
Tk_PhotoImageBlock *blockPtr);
static int StringMatchPPM(Tcl_Obj *dataObj, Tcl_Obj *format,
int *widthPtr, int *heightPtr, Tcl_Interp *interp);
static int StringReadPPM(Tcl_Interp *interp, Tcl_Obj *dataObj,
Tcl_Obj *format, Tk_PhotoHandle imageHandle,
int destX, int destY, int width, int height,
int srcX, int srcY);
Tk_PhotoImageFormat tkImgFmtPPM = {
"ppm", /* name */
FileMatchPPM, /* fileMatchProc */
StringMatchPPM, /* stringMatchProc */
FileReadPPM, /* fileReadProc */
StringReadPPM, /* stringReadProc */
FileWritePPM, /* fileWriteProc */
StringWritePPM, /* stringWriteProc */
NULL
};
/*
* Prototypes for local functions defined in this file:
*/
static int ReadPPMFileHeader(Tcl_Channel chan, int *widthPtr,
int *heightPtr, int *maxIntensityPtr);
static int ReadPPMStringHeader(Tcl_Obj *dataObj, int *widthPtr,
int *heightPtr, int *maxIntensityPtr,
unsigned char **dataBufferPtr, int *dataSizePtr);
/*
*----------------------------------------------------------------------
*
* FileMatchPPM --
*
* This function is invoked by the photo image type to see if a file
* contains image data in PPM format.
*
* Results:
* The return value is >0 if the first characters in file "f" look like
* PPM data, and 0 otherwise.
*
* Side effects:
* The access position in f may change.
*
*----------------------------------------------------------------------
*/
static int
FileMatchPPM(
Tcl_Channel chan, /* The image file, open for reading. */
const char *fileName, /* The name of the image file. */
Tcl_Obj *format, /* User-specified format string, or NULL. */
int *widthPtr, int *heightPtr,
/* The dimensions of the image are returned
* here if the file is a valid raw PPM
* file. */
Tcl_Interp *interp) /* unused */
{
int dummy;
return ReadPPMFileHeader(chan, widthPtr, heightPtr, &dummy);
}
/*
*----------------------------------------------------------------------
*
* FileReadPPM --
*
* This function is called by the photo image type to read PPM format
* data from a file and write it into a given photo image.
*
* Results:
* A standard TCL completion code. If TCL_ERROR is returned then an error
* message is left in the interp's result.
*
* Side effects:
* The access position in file f is changed, and new data is added to the
* image given by imageHandle.
*
*----------------------------------------------------------------------
*/
static int
FileReadPPM(
Tcl_Interp *interp, /* Interpreter to use for reporting errors. */
Tcl_Channel chan, /* The image file, open for reading. */
const char *fileName, /* The name of the image file. */
Tcl_Obj *format, /* User-specified format string, or NULL. */
Tk_PhotoHandle imageHandle, /* The photo image to write into. */
int destX, int destY, /* Coordinates of top-left pixel in photo
* image to be written to. */
int width, int height, /* Dimensions of block of photo image to be
* written to. */
int srcX, int srcY) /* Coordinates of top-left pixel to be used in
* image being read. */
{
int fileWidth, fileHeight, maxIntensity;
int nLines, nBytes, h, type, count;
unsigned char *pixelPtr;
Tk_PhotoImageBlock block;
type = ReadPPMFileHeader(chan, &fileWidth, &fileHeight, &maxIntensity);
if (type == 0) {
Tcl_SetObjResult(interp, Tcl_ObjPrintf(
"couldn't read raw PPM header from file \"%s\"", fileName));
Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "NO_HEADER", NULL);
return TCL_ERROR;
}
if ((fileWidth <= 0) || (fileHeight <= 0)) {
Tcl_SetObjResult(interp, Tcl_ObjPrintf(
"PPM image file \"%s\" has dimension(s) <= 0", fileName));
Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "DIMENSIONS", NULL);
return TCL_ERROR;
}
if ((maxIntensity <= 0) || (maxIntensity >= 256)) {
Tcl_SetObjResult(interp, Tcl_ObjPrintf(
"PPM image file \"%s\" has bad maximum intensity value %d",
fileName, maxIntensity));
Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "INTENSITY", NULL);
return TCL_ERROR;
}
if ((srcX + width) > fileWidth) {
width = fileWidth - srcX;
}
if ((srcY + height) > fileHeight) {
height = fileHeight - srcY;
}
if ((width <= 0) || (height <= 0)
|| (srcX >= fileWidth) || (srcY >= fileHeight)) {
return TCL_OK;
}
if (type == PGM) {
block.pixelSize = 1;
block.offset[0] = 0;
block.offset[1] = 0;
block.offset[2] = 0;
} else {
block.pixelSize = 3;
block.offset[0] = 0;
block.offset[1] = 1;
block.offset[2] = 2;
}
block.offset[3] = 0;
block.width = width;
block.pitch = block.pixelSize * fileWidth;
if (Tk_PhotoExpand(interp, imageHandle,
destX + width, destY + height) != TCL_OK) {
return TCL_ERROR;
}
if (srcY > 0) {
Tcl_Seek(chan, (Tcl_WideInt)(srcY * block.pitch), SEEK_CUR);
}
nLines = (MAX_MEMORY + block.pitch - 1) / block.pitch;
if (nLines > height) {
nLines = height;
}
if (nLines <= 0) {
nLines = 1;
}
nBytes = nLines * block.pitch;
pixelPtr = ckalloc(nBytes);
block.pixelPtr = pixelPtr + srcX * block.pixelSize;
for (h = height; h > 0; h -= nLines) {
if (nLines > h) {
nLines = h;
nBytes = nLines * block.pitch;
}
count = Tcl_Read(chan, (char *) pixelPtr, nBytes);
if (count != nBytes) {
Tcl_SetObjResult(interp, Tcl_ObjPrintf(
"error reading PPM image file \"%s\": %s", fileName,
Tcl_Eof(chan)?"not enough data":Tcl_PosixError(interp)));
if (Tcl_Eof(chan)) {
Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "EOF", NULL);
}
ckfree(pixelPtr);
return TCL_ERROR;
}
if (maxIntensity != 255) {
unsigned char *p;
for (p = pixelPtr; count > 0; count--, p++) {
*p = (((int) *p) * 255)/maxIntensity;
}
}
block.height = nLines;
if (Tk_PhotoPutBlock(interp, imageHandle, &block, destX, destY,
width, nLines, TK_PHOTO_COMPOSITE_SET) != TCL_OK) {
ckfree(pixelPtr);
return TCL_ERROR;
}
destY += nLines;
}
ckfree(pixelPtr);
return TCL_OK;
}
/*
*----------------------------------------------------------------------
*
* FileWritePPM --
*
* This function is invoked to write image data to a file in PPM format
* (although we can read PGM files, we never write them).
*
* Results:
* A standard TCL completion code. If TCL_ERROR is returned then an error
* message is left in the interp's result.
*
* Side effects:
* Data is written to the file given by "fileName".
*
*----------------------------------------------------------------------
*/
static int
FileWritePPM(
Tcl_Interp *interp,
const char *fileName,
Tcl_Obj *format,
Tk_PhotoImageBlock *blockPtr)
{
Tcl_Channel chan;
int w, h, greenOffset, blueOffset, nBytes;
unsigned char *pixelPtr, *pixLinePtr;
char header[16 + TCL_INTEGER_SPACE * 2];
chan = Tcl_OpenFileChannel(interp, fileName, "w", 0666);
if (chan == NULL) {
return TCL_ERROR;
}
if (Tcl_SetChannelOption(interp, chan, "-translation", "binary")
!= TCL_OK) {
Tcl_Close(NULL, chan);
return TCL_ERROR;
}
if (Tcl_SetChannelOption(interp, chan, "-encoding", "binary")
!= TCL_OK) {
Tcl_Close(NULL, chan);
return TCL_ERROR;
}
sprintf(header, "P6\n%d %d\n255\n", blockPtr->width, blockPtr->height);
Tcl_Write(chan, header, -1);
pixLinePtr = blockPtr->pixelPtr + blockPtr->offset[0];
greenOffset = blockPtr->offset[1] - blockPtr->offset[0];
blueOffset = blockPtr->offset[2] - blockPtr->offset[0];
if ((greenOffset == 1) && (blueOffset == 2) && (blockPtr->pixelSize == 3)
&& (blockPtr->pitch == (blockPtr->width * 3))) {
nBytes = blockPtr->height * blockPtr->pitch;
if (Tcl_Write(chan, (char *) pixLinePtr, nBytes) != nBytes) {
goto writeerror;
}
} else {
for (h = blockPtr->height; h > 0; h--) {
pixelPtr = pixLinePtr;
for (w = blockPtr->width; w > 0; w--) {
if ( Tcl_Write(chan,(char *)&pixelPtr[0], 1) == -1 ||
Tcl_Write(chan,(char *)&pixelPtr[greenOffset],1)==-1 ||
Tcl_Write(chan,(char *)&pixelPtr[blueOffset],1) ==-1) {
goto writeerror;
}
pixelPtr += blockPtr->pixelSize;
}
pixLinePtr += blockPtr->pitch;
}
}
if (Tcl_Close(NULL, chan) == 0) {
return TCL_OK;
}
chan = NULL;
writeerror:
Tcl_SetObjResult(interp, Tcl_ObjPrintf("error writing \"%s\": %s",
fileName, Tcl_PosixError(interp)));
if (chan != NULL) {
Tcl_Close(NULL, chan);
}
return TCL_ERROR;
}
/*
*----------------------------------------------------------------------
*
* StringWritePPM --
*
* This function is invoked to write image data to a string in PPM
* format.
*
* Results:
* A standard TCL completion code. If TCL_ERROR is returned then an error
* message is left in the interp's result.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
static int
StringWritePPM(
Tcl_Interp *interp,
Tcl_Obj *format,
Tk_PhotoImageBlock *blockPtr)
{
int w, h, size, greenOffset, blueOffset;
unsigned char *pixLinePtr, *byteArray;
char header[16 + TCL_INTEGER_SPACE * 2];
Tcl_Obj *byteArrayObj;
sprintf(header, "P6\n%d %d\n255\n", blockPtr->width, blockPtr->height);
/*
* Construct a byte array of the right size with the header and
* get a pointer to the data part of it.
*/
size = strlen(header);
byteArrayObj = Tcl_NewByteArrayObj((unsigned char *)header, size);
byteArray = Tcl_SetByteArrayLength(byteArrayObj,
size + 3*blockPtr->width*blockPtr->height);
byteArray += size;
pixLinePtr = blockPtr->pixelPtr + blockPtr->offset[0];
greenOffset = blockPtr->offset[1] - blockPtr->offset[0];
blueOffset = blockPtr->offset[2] - blockPtr->offset[0];
/*
* Check if we can do the data move in single action.
*/
if ((greenOffset == 1) && (blueOffset == 2) && (blockPtr->pixelSize == 3)
&& (blockPtr->pitch == (blockPtr->width * 3))) {
memcpy(byteArray, pixLinePtr,
(unsigned)blockPtr->height * blockPtr->pitch);
} else {
for (h = blockPtr->height; h > 0; h--) {
unsigned char *pixelPtr = pixLinePtr;
for (w = blockPtr->width; w > 0; w--) {
*byteArray++ = pixelPtr[0];
*byteArray++ = pixelPtr[greenOffset];
*byteArray++ = pixelPtr[blueOffset];
pixelPtr += blockPtr->pixelSize;
}
pixLinePtr += blockPtr->pitch;
}
}
/*
* Return the object in the interpreter result.
*/
Tcl_SetObjResult(interp, byteArrayObj);
return TCL_OK;
}
/*
*----------------------------------------------------------------------
*
* StringMatchPPM --
*
* This function is invoked by the photo image type to see if a string
* contains image data in PPM format.
*
* Results:
* The return value is >0 if the first characters in file "f" look like
* PPM data, and 0 otherwise.
*
* Side effects:
* The access position in f may change.
*
*----------------------------------------------------------------------
*/
static int
StringMatchPPM(
Tcl_Obj *dataObj, /* The image data. */
Tcl_Obj *format, /* User-specified format string, or NULL. */
int *widthPtr, int *heightPtr,
/* The dimensions of the image are returned
* here if the file is a valid raw PPM
* file. */
Tcl_Interp *interp) /* unused */
{
int dummy;
return ReadPPMStringHeader(dataObj, widthPtr, heightPtr,
&dummy, NULL, NULL);
}
/*
*----------------------------------------------------------------------
*
* StringReadPPM --
*
* This function is called by the photo image type to read PPM format
* data from a string and write it into a given photo image.
*
* Results:
* A standard TCL completion code. If TCL_ERROR is returned then an error
* message is left in the interp's result.
*
* Side effects:
* New data is added to the image given by imageHandle.
*
*----------------------------------------------------------------------
*/
static int
StringReadPPM(
Tcl_Interp *interp, /* Interpreter to use for reporting errors. */
Tcl_Obj *dataObj, /* The image data. */
Tcl_Obj *format, /* User-specified format string, or NULL. */
Tk_PhotoHandle imageHandle, /* The photo image to write into. */
int destX, int destY, /* Coordinates of top-left pixel in photo
* image to be written to. */
int width, int height, /* Dimensions of block of photo image to be
* written to. */
int srcX, int srcY) /* Coordinates of top-left pixel to be used in
* image being read. */
{
int fileWidth, fileHeight, maxIntensity;
int nLines, nBytes, h, type, count, dataSize;
unsigned char *pixelPtr, *dataBuffer;
Tk_PhotoImageBlock block;
type = ReadPPMStringHeader(dataObj, &fileWidth, &fileHeight,
&maxIntensity, &dataBuffer, &dataSize);
if (type == 0) {
Tcl_SetObjResult(interp, Tcl_NewStringObj(
"couldn't read raw PPM header from string", -1));
Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "NO_HEADER", NULL);
return TCL_ERROR;
}
if ((fileWidth <= 0) || (fileHeight <= 0)) {
Tcl_SetObjResult(interp, Tcl_NewStringObj(
"PPM image data has dimension(s) <= 0", -1));
Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "DIMENSIONS", NULL);
return TCL_ERROR;
}
if ((maxIntensity <= 0) || (maxIntensity >= 256)) {
Tcl_SetObjResult(interp, Tcl_ObjPrintf(
"PPM image data has bad maximum intensity value %d",
maxIntensity));
Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "INTENSITY", NULL);
return TCL_ERROR;
}
if ((srcX + width) > fileWidth) {
width = fileWidth - srcX;
}
if ((srcY + height) > fileHeight) {
height = fileHeight - srcY;
}
if ((width <= 0) || (height <= 0)
|| (srcX >= fileWidth) || (srcY >= fileHeight)) {
return TCL_OK;
}
if (type == PGM) {
block.pixelSize = 1;
block.offset[0] = 0;
block.offset[1] = 0;
block.offset[2] = 0;
} else {
block.pixelSize = 3;
block.offset[0] = 0;
block.offset[1] = 1;
block.offset[2] = 2;
}
block.offset[3] = 0;
block.width = width;
block.pitch = block.pixelSize * fileWidth;
if (srcY > 0) {
dataBuffer += srcY * block.pitch;
dataSize -= srcY * block.pitch;
}
if (maxIntensity == 255) {
/*
* We have all the data in memory, so write everything in one go.
*/
if (block.pitch*height > dataSize) {
Tcl_SetObjResult(interp, Tcl_NewStringObj(
"truncated PPM data", -1));
Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "TRUNCATED", NULL);
return TCL_ERROR;
}
block.pixelPtr = dataBuffer + srcX * block.pixelSize;
block.height = height;
return Tk_PhotoPutBlock(interp, imageHandle, &block, destX, destY,
width, height, TK_PHOTO_COMPOSITE_SET);
}
if (Tk_PhotoExpand(interp, imageHandle,
destX + width, destY + height) != TCL_OK) {
return TCL_ERROR;
}
nLines = (MAX_MEMORY + block.pitch - 1) / block.pitch;
if (nLines > height) {
nLines = height;
}
if (nLines <= 0) {
nLines = 1;
}
nBytes = nLines * block.pitch;
pixelPtr = ckalloc(nBytes);
block.pixelPtr = pixelPtr + srcX * block.pixelSize;
for (h = height; h > 0; h -= nLines) {
unsigned char *p;
if (nLines > h) {
nLines = h;
nBytes = nLines * block.pitch;
}
if (dataSize < nBytes) {
ckfree(pixelPtr);
Tcl_SetObjResult(interp, Tcl_NewStringObj(
"truncated PPM data", -1));
Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "TRUNCATED", NULL);
return TCL_ERROR;
}
for (p=pixelPtr,count=nBytes ; count>0 ; count--,p++,dataBuffer++) {
*p = (((int) *dataBuffer) * 255)/maxIntensity;
}
dataSize -= nBytes;
block.height = nLines;
if (Tk_PhotoPutBlock(interp, imageHandle, &block, destX, destY,
width, nLines, TK_PHOTO_COMPOSITE_SET) != TCL_OK) {
ckfree(pixelPtr);
return TCL_ERROR;
}
destY += nLines;
}
ckfree(pixelPtr);
return TCL_OK;
}
/*
*----------------------------------------------------------------------
*
* ReadPPMFileHeader --
*
* This function reads the PPM header from the beginning of a PPM file
* and returns information from the header.
*
* Results:
* The return value is PGM if file "f" appears to start with a valid PGM
* header, PPM if "f" appears to start with a valid PPM header, and 0
* otherwise. If the header is valid, then *widthPtr and *heightPtr are
* modified to hold the dimensions of the image and *maxIntensityPtr is
* modified to hold the value of a "fully on" intensity value.
*
* Side effects:
* The access position in f advances.
*
*----------------------------------------------------------------------
*/
static int
ReadPPMFileHeader(
Tcl_Channel chan, /* Image file to read the header from. */
int *widthPtr, int *heightPtr,
/* The dimensions of the image are returned
* here. */
int *maxIntensityPtr) /* The maximum intensity value for the image
* is stored here. */
{
#define BUFFER_SIZE 1000
char buffer[BUFFER_SIZE], c;
int i, numFields, type = 0;
/*
* Read 4 space-separated fields from the file, ignoring comments (any
* line that starts with "#").
*/
if (Tcl_Read(chan, &c, 1) != 1) {
return 0;
}
i = 0;
for (numFields = 0; numFields < 4; numFields++) {
/*
* Skip comments and white space.
*/
while (1) {
while (isspace(UCHAR(c))) {
if (Tcl_Read(chan, &c, 1) != 1) {
return 0;
}
}
if (c != '#') {
break;
}
do {
if (Tcl_Read(chan, &c, 1) != 1) {
return 0;
}
} while (c != '\n');
}
/*
* Read a field (everything up to the next white space).
*/
while (!isspace(UCHAR(c))) {
if (i < (BUFFER_SIZE-2)) {
buffer[i] = c;
i++;
}
if (Tcl_Read(chan, &c, 1) != 1) {
goto done;
}
}
if (i < (BUFFER_SIZE-1)) {
buffer[i] = ' ';
i++;
}
}
done:
buffer[i] = 0;
/*
* Parse the fields, which are: id, width, height, maxIntensity.
*/
if (strncmp(buffer, "P6 ", 3) == 0) {
type = PPM;
} else if (strncmp(buffer, "P5 ", 3) == 0) {
type = PGM;
} else {
return 0;
}
if (sscanf(buffer+3, "%d %d %d", widthPtr, heightPtr, maxIntensityPtr)
!= 3) {
return 0;
}
return type;
}
/*
*----------------------------------------------------------------------
*
* ReadPPMStringHeader --
*
* This function reads the PPM header from the beginning of a PPM-format
* string and returns information from the header.
*
* Results:
* The return value is PGM if the string appears to start with a valid
* PGM header, PPM if the string appears to start with a valid PPM
* header, and 0 otherwise. If the header is valid, then *widthPtr and
* *heightPtr are modified to hold the dimensions of the image and
* *maxIntensityPtr is modified to hold the value of a "fully on"
* intensity value.
*
* Side effects:
* None
*
*----------------------------------------------------------------------
*/
static int
ReadPPMStringHeader(
Tcl_Obj *dataPtr, /* Object to read the header from. */
int *widthPtr, int *heightPtr,
/* The dimensions of the image are returned
* here. */
int *maxIntensityPtr, /* The maximum intensity value for the image
* is stored here. */
unsigned char **dataBufferPtr,
int *dataSizePtr)
{
#define BUFFER_SIZE 1000
char buffer[BUFFER_SIZE], c;
int i, numFields, dataSize, type = 0;
unsigned char *dataBuffer;
dataBuffer = Tcl_GetByteArrayFromObj(dataPtr, &dataSize);
/*
* Read 4 space-separated fields from the string, ignoring comments (any
* line that starts with "#").
*/
if (dataSize-- < 1) {
return 0;
}
c = (char) (*dataBuffer++);
i = 0;
for (numFields = 0; numFields < 4; numFields++) {
/*
* Skip comments and white space.
*/
while (1) {
while (isspace(UCHAR(c))) {
if (dataSize-- < 1) {
return 0;
}
c = (char) (*dataBuffer++);
}
if (c != '#') {
break;
}
do {
if (dataSize-- < 1) {
return 0;
}
c = (char) (*dataBuffer++);
} while (c != '\n');
}
/*
* Read a field (everything up to the next white space).
*/
while (!isspace(UCHAR(c))) {
if (i < (BUFFER_SIZE-2)) {
buffer[i] = c;
i++;
}
if (dataSize-- < 1) {
goto done;
}
c = (char) (*dataBuffer++);
}
if (i < (BUFFER_SIZE-1)) {
buffer[i] = ' ';
i++;
}
}
done:
buffer[i] = 0;
/*
* Parse the fields, which are: id, width, height, maxIntensity.
*/
if (strncmp(buffer, "P6 ", 3) == 0) {
type = PPM;
} else if (strncmp(buffer, "P5 ", 3) == 0) {
type = PGM;
} else {
return 0;
}
if (sscanf(buffer+3, "%d %d %d", widthPtr, heightPtr, maxIntensityPtr)
!= 3) {
return 0;
}
if (dataBufferPtr != NULL) {
*dataBufferPtr = dataBuffer;
*dataSizePtr = dataSize;
}
return type;
}
/*
* Local Variables:
* mode: c
* c-basic-offset: 4
* fill-column: 78
* End:
*/
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