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Diffstat (limited to 'generic/tkImgPPM.c')
| -rw-r--r-- | generic/tkImgPPM.c | 421 |
1 files changed, 421 insertions, 0 deletions
diff --git a/generic/tkImgPPM.c b/generic/tkImgPPM.c new file mode 100644 index 0000000..3a54003 --- /dev/null +++ b/generic/tkImgPPM.c @@ -0,0 +1,421 @@ +/* + * 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; +} |