428 lines
11 KiB
C
428 lines
11 KiB
C
/*
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* tkImgPPM.c --
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*
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* A photo image file handler for PPM (Portable PixMap) files.
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*
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* Copyright (c) 1994 The Australian National University.
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* Copyright (c) 1994-1997 Sun Microsystems, Inc.
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*
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* See the file "license.terms" for information on usage and redistribution
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* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
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*
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* Author: Paul Mackerras (paulus@cs.anu.edu.au),
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* Department of Computer Science,
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* Australian National University.
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*
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* SCCS: @(#) tkImgPPM.c 1.16 97/10/28 14:51:46
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*/
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#include "tkInt.h"
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#include "tkPort.h"
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/*
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* The maximum amount of memory to allocate for data read from the
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* file. If we need more than this, we do it in pieces.
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*/
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#define MAX_MEMORY 10000 /* don't allocate > 10KB */
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/*
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* Define PGM and PPM, i.e. gray images and color images.
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*/
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#define PGM 1
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#define PPM 2
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/*
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* The format record for the PPM file format:
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*/
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static int FileMatchPPM _ANSI_ARGS_((Tcl_Channel chan,
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char *fileName, char *formatString,
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int *widthPtr, int *heightPtr));
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static int FileReadPPM _ANSI_ARGS_((Tcl_Interp *interp,
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Tcl_Channel chan, char *fileName,
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char *formatString, Tk_PhotoHandle imageHandle,
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int destX, int destY, int width, int height,
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int srcX, int srcY));
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static int FileWritePPM _ANSI_ARGS_((Tcl_Interp *interp,
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char *fileName, char *formatString,
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Tk_PhotoImageBlock *blockPtr));
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Tk_PhotoImageFormat tkImgFmtPPM = {
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"PPM", /* name */
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FileMatchPPM, /* fileMatchProc */
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NULL, /* stringMatchProc */
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FileReadPPM, /* fileReadProc */
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NULL, /* stringReadProc */
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FileWritePPM, /* fileWriteProc */
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NULL, /* stringWriteProc */
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};
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/*
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* Prototypes for local procedures defined in this file:
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*/
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static int ReadPPMFileHeader _ANSI_ARGS_((Tcl_Channel chan,
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int *widthPtr, int *heightPtr,
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int *maxIntensityPtr));
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/*
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*----------------------------------------------------------------------
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*
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* FileMatchPPM --
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*
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* This procedure is invoked by the photo image type to see if
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* a file contains image data in PPM format.
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*
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* Results:
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* The return value is >0 if the first characters in file "f" look
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* like PPM data, and 0 otherwise.
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*
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* Side effects:
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* The access position in f may change.
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*
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*----------------------------------------------------------------------
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*/
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static int
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FileMatchPPM(chan, fileName, formatString, widthPtr, heightPtr)
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Tcl_Channel chan; /* The image file, open for reading. */
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char *fileName; /* The name of the image file. */
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char *formatString; /* User-specified format string, or NULL. */
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int *widthPtr, *heightPtr; /* The dimensions of the image are
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* returned here if the file is a valid
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* raw PPM file. */
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{
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int dummy;
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return ReadPPMFileHeader(chan, widthPtr, heightPtr, &dummy);
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}
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/*
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*----------------------------------------------------------------------
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*
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* FileReadPPM --
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*
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* This procedure is called by the photo image type to read
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* PPM format data from a file and write it into a given
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* photo image.
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*
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* Results:
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* A standard TCL completion code. If TCL_ERROR is returned
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* then an error message is left in interp->result.
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*
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* Side effects:
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* The access position in file f is changed, and new data is
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* added to the image given by imageHandle.
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*
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*----------------------------------------------------------------------
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*/
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static int
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FileReadPPM(interp, chan, fileName, formatString, imageHandle, destX, destY,
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width, height, srcX, srcY)
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Tcl_Interp *interp; /* Interpreter to use for reporting errors. */
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Tcl_Channel chan; /* The image file, open for reading. */
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char *fileName; /* The name of the image file. */
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char *formatString; /* User-specified format string, or NULL. */
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Tk_PhotoHandle imageHandle; /* The photo image to write into. */
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int destX, destY; /* Coordinates of top-left pixel in
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* photo image to be written to. */
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int width, height; /* Dimensions of block of photo image to
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* be written to. */
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int srcX, srcY; /* Coordinates of top-left pixel to be used
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* in image being read. */
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{
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int fileWidth, fileHeight, maxIntensity;
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int nLines, nBytes, h, type, count;
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unsigned char *pixelPtr;
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Tk_PhotoImageBlock block;
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type = ReadPPMFileHeader(chan, &fileWidth, &fileHeight, &maxIntensity);
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if (type == 0) {
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Tcl_AppendResult(interp, "couldn't read raw PPM header from file \"",
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fileName, "\"", NULL);
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return TCL_ERROR;
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}
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if ((fileWidth <= 0) || (fileHeight <= 0)) {
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Tcl_AppendResult(interp, "PPM image file \"", fileName,
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"\" has dimension(s) <= 0", (char *) NULL);
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return TCL_ERROR;
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}
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if ((maxIntensity <= 0) || (maxIntensity >= 256)) {
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char buffer[30];
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sprintf(buffer, "%d", maxIntensity);
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Tcl_AppendResult(interp, "PPM image file \"", fileName,
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"\" has bad maximum intensity value ", buffer,
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(char *) NULL);
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return TCL_ERROR;
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}
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if ((srcX + width) > fileWidth) {
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width = fileWidth - srcX;
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}
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if ((srcY + height) > fileHeight) {
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height = fileHeight - srcY;
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}
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if ((width <= 0) || (height <= 0)
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|| (srcX >= fileWidth) || (srcY >= fileHeight)) {
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return TCL_OK;
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}
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if (type == PGM) {
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block.pixelSize = 1;
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block.offset[0] = 0;
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block.offset[1] = 0;
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block.offset[2] = 0;
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}
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else {
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block.pixelSize = 3;
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block.offset[0] = 0;
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block.offset[1] = 1;
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block.offset[2] = 2;
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}
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block.width = width;
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block.pitch = block.pixelSize * fileWidth;
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Tk_PhotoExpand(imageHandle, destX + width, destY + height);
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if (srcY > 0) {
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Tcl_Seek(chan, (srcY * block.pitch), SEEK_CUR);
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}
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nLines = (MAX_MEMORY + block.pitch - 1) / block.pitch;
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if (nLines > height) {
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nLines = height;
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}
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if (nLines <= 0) {
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nLines = 1;
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}
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nBytes = nLines * block.pitch;
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pixelPtr = (unsigned char *) ckalloc((unsigned) nBytes);
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block.pixelPtr = pixelPtr + srcX * block.pixelSize;
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for (h = height; h > 0; h -= nLines) {
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if (nLines > h) {
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nLines = h;
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nBytes = nLines * block.pitch;
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}
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count = Tcl_Read(chan, (char *) pixelPtr, nBytes);
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if (count != nBytes) {
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Tcl_AppendResult(interp, "error reading PPM image file \"",
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fileName, "\": ",
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#ifdef BGLK_CODE
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Tcl_Eof(chan) ?
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(char *)"not enough data" :
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(char *)Tcl_PosixError(interp),
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#else
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Tcl_Eof(chan) ? "not enough data" : Tcl_PosixError(interp),
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#endif
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(char *) NULL);
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ckfree((char *) pixelPtr);
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return TCL_ERROR;
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}
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if (maxIntensity != 255) {
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unsigned char *p;
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for (p = pixelPtr; count > 0; count--, p++) {
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*p = (((int) *p) * 255)/maxIntensity;
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}
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}
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block.height = nLines;
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Tk_PhotoPutBlock(imageHandle, &block, destX, destY, width, nLines);
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destY += nLines;
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}
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ckfree((char *) pixelPtr);
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return TCL_OK;
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}
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/*
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*----------------------------------------------------------------------
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*
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* FileWritePPM --
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*
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* This procedure is invoked to write image data to a file in PPM
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* format.
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*
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* Results:
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* A standard TCL completion code. If TCL_ERROR is returned
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* then an error message is left in interp->result.
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*
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* Side effects:
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* Data is written to the file given by "fileName".
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*
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*----------------------------------------------------------------------
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*/
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static int
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FileWritePPM(interp, fileName, formatString, blockPtr)
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Tcl_Interp *interp;
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char *fileName;
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char *formatString;
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Tk_PhotoImageBlock *blockPtr;
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{
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Tcl_Channel chan;
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int w, h;
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int greenOffset, blueOffset, nBytes;
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unsigned char *pixelPtr, *pixLinePtr;
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char header[30];
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chan = Tcl_OpenFileChannel(interp, fileName, "w", 0666);
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if (chan == NULL) {
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return TCL_ERROR;
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}
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sprintf(header, "P6\n%d %d\n255\n", blockPtr->width, blockPtr->height);
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Tcl_Write(chan, header, -1);
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pixLinePtr = blockPtr->pixelPtr + blockPtr->offset[0];
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greenOffset = blockPtr->offset[1] - blockPtr->offset[0];
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blueOffset = blockPtr->offset[2] - blockPtr->offset[0];
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if ((greenOffset == 1) && (blueOffset == 2) && (blockPtr->pixelSize == 3)
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&& (blockPtr->pitch == (blockPtr->width * 3))) {
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nBytes = blockPtr->height * blockPtr->pitch;
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if (Tcl_Write(chan, (char *) pixLinePtr, nBytes) != nBytes) {
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goto writeerror;
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}
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} else {
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for (h = blockPtr->height; h > 0; h--) {
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pixelPtr = pixLinePtr;
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for (w = blockPtr->width; w > 0; w--) {
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if ((Tcl_Write(chan, (char *) &pixelPtr[0], 1) == -1)
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|| (Tcl_Write(chan, (char *) &pixelPtr[greenOffset], 1) == -1)
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|| (Tcl_Write(chan, (char *) &pixelPtr[blueOffset], 1) == -1)) {
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goto writeerror;
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}
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pixelPtr += blockPtr->pixelSize;
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}
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pixLinePtr += blockPtr->pitch;
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}
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}
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if (Tcl_Close(NULL, chan) == 0) {
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return TCL_OK;
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}
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chan = NULL;
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writeerror:
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Tcl_AppendResult(interp, "error writing \"", fileName, "\": ",
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Tcl_PosixError(interp), (char *) NULL);
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if (chan != NULL) {
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Tcl_Close(NULL, chan);
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}
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return TCL_ERROR;
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}
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/*
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*----------------------------------------------------------------------
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*
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* ReadPPMFileHeader --
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*
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* This procedure reads the PPM header from the beginning of a
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* PPM file and returns information from the header.
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*
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* Results:
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* The return value is PGM if file "f" appears to start with
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* a valid PGM header, PPM if "f" appears to start with a valid
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* PPM header, and 0 otherwise. If the header is valid,
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* then *widthPtr and *heightPtr are modified to hold the
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* dimensions of the image and *maxIntensityPtr is modified to
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* hold the value of a "fully on" intensity value.
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*
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* Side effects:
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* The access position in f advances.
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*
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*----------------------------------------------------------------------
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*/
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static int
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ReadPPMFileHeader(chan, widthPtr, heightPtr, maxIntensityPtr)
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Tcl_Channel chan; /* Image file to read the header from */
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int *widthPtr, *heightPtr; /* The dimensions of the image are
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* returned here. */
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int *maxIntensityPtr; /* The maximum intensity value for
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* the image is stored here. */
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{
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#define BUFFER_SIZE 1000
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char buffer[BUFFER_SIZE];
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int i, numFields, firstInLine;
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int type = 0;
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char c;
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/*
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* Read 4 space-separated fields from the file, ignoring
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* comments (any line that starts with "#").
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*/
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if (Tcl_Read(chan, &c, 1) != 1) {
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return 0;
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}
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firstInLine = 1;
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i = 0;
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for (numFields = 0; numFields < 4; numFields++) {
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/*
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* Skip comments and white space.
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*/
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while (1) {
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while (isspace(UCHAR(c))) {
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firstInLine = (c == '\n');
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if (Tcl_Read(chan, &c, 1) != 1) {
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return 0;
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}
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}
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if (c != '#') {
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break;
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}
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do {
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if (Tcl_Read(chan, &c, 1) != 1) {
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return 0;
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}
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} while (c != '\n');
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firstInLine = 1;
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}
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/*
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* Read a field (everything up to the next white space).
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*/
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while (!isspace(UCHAR(c))) {
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if (i < (BUFFER_SIZE-2)) {
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buffer[i] = c;
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i++;
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}
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if (Tcl_Read(chan, &c, 1) != 1) {
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goto done;
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}
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}
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if (i < (BUFFER_SIZE-1)) {
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buffer[i] = ' ';
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i++;
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}
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firstInLine = 0;
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}
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done:
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buffer[i] = 0;
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/*
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* Parse the fields, which are: id, width, height, maxIntensity.
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*/
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if (strncmp(buffer, "P6 ", 3) == 0) {
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type = PPM;
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} else if (strncmp(buffer, "P5 ", 3) == 0) {
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type = PGM;
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} else {
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return 0;
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}
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if (sscanf(buffer+3, "%d %d %d", widthPtr, heightPtr, maxIntensityPtr)
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!= 3) {
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return 0;
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}
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return type;
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}
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