/*
* 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.
*
* RCS: @(#) $Id: tkImgPPM.c,v 1.10 2002/06/14 13:35:48 dkf Exp $
*/
#if 0
/*
* The way perl/Tk's equivelent to stubs works makes it
* nessary to convert this to new style
*/
#define USE_OLD_IMAGE
#endif
#include "tkInt.h"
#include "tkPort.h"
#include "tkVMacro.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 _ANSI_ARGS_((Tcl_Channel chan,
Tcl_Obj *fileName, Tcl_Obj *formatString,
int *widthPtr, int *heightPtr, Tcl_Interp *interp));
static int FileReadPPM _ANSI_ARGS_((Tcl_Interp *interp,
Tcl_Channel chan, Tcl_Obj *fileName,
Tcl_Obj *formatString, Tk_PhotoHandle imageHandle,
int destX, int destY, int width, int height,
int srcX, int srcY));
static int FileWritePPM _ANSI_ARGS_((Tcl_Interp *interp,
char *fileName, Tcl_Obj *formatString,
Tk_PhotoImageBlock *blockPtr));
Tk_PhotoImageFormat tkImgFmtPPM = {
"PPM", /* name */
FileMatchPPM, /* fileMatchProc */
NULL, /* stringMatchProc */
FileReadPPM, /* fileReadProc */
NULL, /* stringReadProc */
FileWritePPM, /* fileWriteProc */
NULL, /* stringWriteProc */
};
/*
* Prototypes for local procedures defined in this file:
*/
static int ReadPPMFileHeader _ANSI_ARGS_((Tcl_Channel chan,
int *widthPtr, int *heightPtr,
int *maxIntensityPtr));
/*
*----------------------------------------------------------------------
*
* FileMatchPPM --
*
* This procedure 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(chan, fileName, formatString, widthPtr, heightPtr, interp)
Tcl_Channel chan; /* The image file, open for reading. */
Tcl_Obj *fileName; /* The name of the image file. */
Tcl_Obj *formatString; /* User-specified format string, or NULL. */
int *widthPtr, *heightPtr; /* The dimensions of the image are
* returned here if the file is a valid
* raw PPM file. */
Tcl_Interp *interp;
{
int dummy;
return ReadPPMFileHeader(chan, widthPtr, heightPtr, &dummy);
}
/*
*----------------------------------------------------------------------
*
* FileReadPPM --
*
* This procedure 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(interp, chan, fileNameObj, formatString, imageHandle, destX, destY,
width, height, srcX, srcY)
Tcl_Interp *interp; /* Interpreter to use for reporting errors. */
Tcl_Channel chan; /* The image file, open for reading. */
Tcl_Obj *fileNameObj; /* The name of the image file. */
Tcl_Obj *formatString; /* User-specified format string, or NULL. */
Tk_PhotoHandle imageHandle; /* The photo image to write into. */
int destX, destY; /* Coordinates of top-left pixel in
* photo image to be written to. */
int width, height; /* Dimensions of block of photo image to
* be written to. */
int srcX, 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;
char *fileName =Tcl_GetString(fileNameObj);
type = ReadPPMFileHeader(chan, &fileWidth, &fileHeight, &maxIntensity);
if (type == 0) {
Tcl_AppendResult(interp, "couldn't read raw PPM header from file \"",
fileName, "\"", NULL);
return TCL_ERROR;
}
if ((fileWidth <= 0) || (fileHeight <= 0)) {
Tcl_AppendResult(interp, "PPM image file \"", fileName,
"\" has dimension(s) <= 0", (char *) NULL);
return TCL_ERROR;
}
if ((maxIntensity <= 0) || (maxIntensity >= 256)) {
char buffer[TCL_INTEGER_SPACE];
sprintf(buffer, "%d", maxIntensity);
Tcl_AppendResult(interp, "PPM image file \"", fileName,
"\" has bad maximum intensity value ", buffer,
(char *) 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;
Tk_PhotoExpand(imageHandle, destX + width, destY + height);
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 = (unsigned char *) ckalloc((unsigned) 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_AppendResult(interp, "error reading PPM image file \"",
fileName, "\": ",
Tcl_Eof(chan) ? "not enough data" : Tcl_PosixError(interp),
(char *) NULL);
ckfree((char *) 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;
Tk_PhotoPutBlock(imageHandle, &block, destX, destY, width, nLines,
TK_PHOTO_COMPOSITE_SET);
destY += nLines;
}
ckfree((char *) pixelPtr);
return TCL_OK;
}
/*
*----------------------------------------------------------------------
*
* FileWritePPM --
*
* This procedure is invoked to write image data to a file 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:
* Data is written to the file given by "fileName".
*
*----------------------------------------------------------------------
*/
static int
FileWritePPM(interp, fileName, formatString, blockPtr)
Tcl_Interp *interp;
char *fileName;
Tcl_Obj *formatString;
Tk_PhotoImageBlock *blockPtr;
{
Tcl_Channel chan;
int w, h;
int 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_AppendResult(interp, "error writing \"", fileName, "\": ",
Tcl_PosixError(interp), (char *) NULL);
if (chan != NULL) {
Tcl_Close(NULL, chan);
}
return TCL_ERROR;
}
/*
*----------------------------------------------------------------------
*
* ReadPPMFileHeader --
*
* This procedure 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(chan, widthPtr, heightPtr, maxIntensityPtr)
Tcl_Channel chan; /* Image file to read the header from */
int *widthPtr, *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];
int i, numFields;
int type = 0;
char c;
/*
* 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;
}