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[/] [or1k/] [tags/] [start/] [insight/] [tk/] [generic/] [tkImgPPM.c] - Rev 1765
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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. * * RCS: @(#) $Id: tkImgPPM.c,v 1.1.1.1 2002-01-16 10:25:52 markom Exp $ */ #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; }