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-rw-r--r--generic/tkImgPPM.c421
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diff --git a/generic/tkImgPPM.c b/generic/tkImgPPM.c
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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.
+ *
+ * SCCS: @(#) tkImgPPM.c 1.16 97/10/28 14:51:46
+ */
+
+#include "tkInt.h"
+#include "tkPort.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,
+ char *fileName, char *formatString,
+ int *widthPtr, int *heightPtr));
+static int FileReadPPM _ANSI_ARGS_((Tcl_Interp *interp,
+ Tcl_Channel chan, char *fileName,
+ char *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, char *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)
+ Tcl_Channel chan; /* The image file, open for reading. */
+ char *fileName; /* The name of the image file. */
+ char *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. */
+{
+ 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 interp->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, fileName, 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. */
+ char *fileName; /* The name of the image file. */
+ char *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;
+
+ 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[30];
+
+ 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.width = width;
+ block.pitch = block.pixelSize * fileWidth;
+
+ Tk_PhotoExpand(imageHandle, destX + width, destY + height);
+
+ if (srcY > 0) {
+ Tcl_Seek(chan, (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);
+ 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 interp->result.
+ *
+ * Side effects:
+ * Data is written to the file given by "fileName".
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+FileWritePPM(interp, fileName, formatString, blockPtr)
+ Tcl_Interp *interp;
+ char *fileName;
+ char *formatString;
+ Tk_PhotoImageBlock *blockPtr;
+{
+ Tcl_Channel chan;
+ int w, h;
+ int greenOffset, blueOffset, nBytes;
+ unsigned char *pixelPtr, *pixLinePtr;
+ char header[30];
+
+ chan = Tcl_OpenFileChannel(interp, fileName, "w", 0666);
+ if (chan == NULL) {
+ 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, firstInLine;
+ 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;
+ }
+ firstInLine = 1;
+ i = 0;
+ for (numFields = 0; numFields < 4; numFields++) {
+ /*
+ * Skip comments and white space.
+ */
+
+ while (1) {
+ while (isspace(UCHAR(c))) {
+ firstInLine = (c == '\n');
+ 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');
+ firstInLine = 1;
+ }
+
+ /*
+ * 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++;
+ }
+ firstInLine = 0;
+ }
+ 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;
+}