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authordkf <donal.k.fellows@manchester.ac.uk>2004-03-27 00:12:21 (GMT)
committerdkf <donal.k.fellows@manchester.ac.uk>2004-03-27 00:12:21 (GMT)
commit44e60258a4be07705c139d5b27563470ef5a95ee (patch)
tree25fac97e00ae651ad800f8dd38f8d6b951b3175a /generic/tkImgPPM.c
parent71d77002995b03c970b348fc731a45ca779988df (diff)
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Allow PPMs to be read from a string. [FRQ 540375]
Diffstat (limited to 'generic/tkImgPPM.c')
-rw-r--r--generic/tkImgPPM.c330
1 files changed, 322 insertions, 8 deletions
diff --git a/generic/tkImgPPM.c b/generic/tkImgPPM.c
index 1f3585e..ac989db 100644
--- a/generic/tkImgPPM.c
+++ b/generic/tkImgPPM.c
@@ -13,7 +13,7 @@
* Department of Computer Science,
* Australian National University.
*
- * RCS: @(#) $Id: tkImgPPM.c,v 1.13 2004/03/26 19:49:40 dgp Exp $
+ * RCS: @(#) $Id: tkImgPPM.c,v 1.14 2004/03/27 00:12:22 dkf Exp $
*/
#include "tkInt.h"
@@ -51,13 +51,21 @@ static int FileWritePPM _ANSI_ARGS_((Tcl_Interp *interp,
Tk_PhotoImageBlock *blockPtr));
static int StringWritePPM _ANSI_ARGS_((Tcl_Interp *interp,
Tcl_Obj *format, Tk_PhotoImageBlock *blockPtr));
+static int StringMatchPPM _ANSI_ARGS_((Tcl_Obj *dataObj,
+ Tcl_Obj *format, int *widthPtr, int *heightPtr,
+ Tcl_Interp *interp));
+static int StringReadPPM _ANSI_ARGS_((Tcl_Interp *interp,
+ Tcl_Obj *dataObj, Tcl_Obj *format,
+ Tk_PhotoHandle imageHandle, int destX, int destY,
+ int width, int height, int srcX, int srcY));
+
Tk_PhotoImageFormat tkImgFmtPPM = {
"ppm", /* name */
FileMatchPPM, /* fileMatchProc */
- NULL, /* stringMatchProc */
+ StringMatchPPM, /* stringMatchProc */
FileReadPPM, /* fileReadProc */
- NULL, /* stringReadProc */
+ StringReadPPM, /* stringReadProc */
FileWritePPM, /* fileWriteProc */
StringWritePPM, /* stringWriteProc */
};
@@ -69,6 +77,10 @@ Tk_PhotoImageFormat tkImgFmtPPM = {
static int ReadPPMFileHeader _ANSI_ARGS_((Tcl_Channel chan,
int *widthPtr, int *heightPtr,
int *maxIntensityPtr));
+static int ReadPPMStringHeader _ANSI_ARGS_((Tcl_Obj *dataObj,
+ int *widthPtr, int *heightPtr,
+ int *maxIntensityPtr,
+ unsigned char **dataBufferPtr, int *dataSizePtr));
/*
*----------------------------------------------------------------------
@@ -151,7 +163,7 @@ FileReadPPM(interp, chan, fileName, format, imageHandle, destX, destY,
}
if ((fileWidth <= 0) || (fileHeight <= 0)) {
Tcl_AppendResult(interp, "PPM image file \"", fileName,
- "\" has dimension(s) <= 0", (char *) NULL);
+ "\" has dimension(s) <= 0", NULL);
return TCL_ERROR;
}
if ((maxIntensity <= 0) || (maxIntensity >= 256)) {
@@ -159,8 +171,7 @@ FileReadPPM(interp, chan, fileName, format, imageHandle, destX, destY,
sprintf(buffer, "%d", maxIntensity);
Tcl_AppendResult(interp, "PPM image file \"", fileName,
- "\" has bad maximum intensity value ", buffer,
- (char *) NULL);
+ "\" has bad maximum intensity value ", buffer, NULL);
return TCL_ERROR;
}
@@ -221,7 +232,7 @@ FileReadPPM(interp, chan, fileName, format, imageHandle, destX, destY,
Tcl_AppendResult(interp, "error reading PPM image file \"",
fileName, "\": ",
Tcl_Eof(chan) ? "not enough data" : Tcl_PosixError(interp),
- (char *) NULL);
+ NULL);
ckfree((char *) pixelPtr);
return TCL_ERROR;
}
@@ -327,7 +338,7 @@ FileWritePPM(interp, fileName, format, blockPtr)
writeerror:
Tcl_AppendResult(interp, "error writing \"", fileName, "\": ",
- Tcl_PosixError(interp), (char *) NULL);
+ Tcl_PosixError(interp), NULL);
if (chan != NULL) {
Tcl_Close(NULL, chan);
}
@@ -409,6 +420,190 @@ StringWritePPM(interp, format, blockPtr)
/*
*----------------------------------------------------------------------
*
+ * StringMatchPPM --
+ *
+ * This procedure is invoked by the photo image type to see if
+ * a string 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
+StringMatchPPM(dataObj, format, widthPtr, heightPtr, interp)
+ Tcl_Obj *dataObj; /* The image data. */
+ Tcl_Obj *format; /* 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; /* unused */
+{
+ int dummy;
+
+ return ReadPPMStringHeader(dataObj, widthPtr, heightPtr,
+ &dummy, NULL, NULL);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * StringReadPPM --
+ *
+ * This procedure is called by the photo image type to read
+ * PPM format data from a string 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:
+ * New data is added to the image given by imageHandle.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+StringReadPPM(interp, dataObj, format, imageHandle, destX, destY,
+ width, height, srcX, srcY)
+ Tcl_Interp *interp; /* Interpreter to use for reporting errors. */
+ Tcl_Obj *dataObj; /* The image data. */
+ Tcl_Obj *format; /* 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, dataSize;
+ unsigned char *pixelPtr, *dataBuffer;
+ Tk_PhotoImageBlock block;
+
+ type = ReadPPMStringHeader(dataObj, &fileWidth, &fileHeight,
+ &maxIntensity, &dataBuffer, &dataSize);
+ if (type == 0) {
+ Tcl_AppendResult(interp, "couldn't read raw PPM header from string",
+ NULL);
+ return TCL_ERROR;
+ }
+ if ((fileWidth <= 0) || (fileHeight <= 0)) {
+ Tcl_AppendResult(interp, "PPM image data has dimension(s) <= 0",
+ NULL);
+ return TCL_ERROR;
+ }
+ if ((maxIntensity <= 0) || (maxIntensity >= 256)) {
+ char buffer[TCL_INTEGER_SPACE];
+
+ sprintf(buffer, "%d", maxIntensity);
+ Tcl_AppendResult(interp,
+ "PPM image data has bad maximum intensity value ", buffer,
+ 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;
+
+ if (srcY > 0) {
+ dataBuffer += srcY * block.pitch;
+ dataSize -= srcY * block.pitch;
+ }
+
+ if (maxIntensity == 255) {
+ /*
+ * We have all the data in memory, so write everything in one
+ * go.
+ */
+ if (block.pitch*height < dataSize) {
+ Tcl_AppendResult(interp, "truncated PPM data", NULL);
+ return TCL_ERROR;
+ }
+ block.pixelPtr = dataBuffer + srcX * block.pixelSize;
+ block.height = height;
+ return Tk_PhotoPutBlock(interp, imageHandle, &block, destX, destY,
+ width, height, TK_PHOTO_COMPOSITE_SET);
+ }
+
+ if (Tk_PhotoExpand(interp, imageHandle,
+ destX + width, destY + height) != TCL_OK) {
+ return TCL_ERROR;
+ }
+
+ 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) {
+ unsigned char *p;
+
+ if (nLines > h) {
+ nLines = h;
+ nBytes = nLines * block.pitch;
+ }
+ if (dataSize < nBytes) {
+ ckfree((char *) pixelPtr);
+ Tcl_AppendResult(interp, "truncated PPM data", NULL);
+ return TCL_ERROR;
+ }
+ for (p=pixelPtr,count=nBytes ; count>0 ; count--,p++,dataBuffer++) {
+ *p = (((int) *dataBuffer) * 255)/maxIntensity;
+ }
+ dataSize -= nBytes;
+ block.height = nLines;
+ if (Tk_PhotoPutBlock(interp, imageHandle, &block, destX, destY,
+ width, nLines, TK_PHOTO_COMPOSITE_SET) != TCL_OK) {
+ ckfree((char *) pixelPtr);
+ return TCL_ERROR;
+ }
+ destY += nLines;
+ }
+
+ ckfree((char *) pixelPtr);
+ return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
* ReadPPMFileHeader --
*
* This procedure reads the PPM header from the beginning of a
@@ -510,3 +705,122 @@ ReadPPMFileHeader(chan, widthPtr, heightPtr, maxIntensityPtr)
}
return type;
}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * ReadPPMStringHeader --
+ *
+ * This procedure reads the PPM header from the beginning of a
+ * PPM-format string and returns information from the header.
+ *
+ * Results:
+ * The return value is PGM if the string appears to start with
+ * a valid PGM header, PPM if the string 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:
+ * None
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+ReadPPMStringHeader(dataPtr, widthPtr, heightPtr, maxIntensityPtr,
+ dataBufferPtr, dataSizePtr)
+ Tcl_Obj *dataPtr; /* Object 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. */
+ unsigned char **dataBufferPtr;
+ int *dataSizePtr;
+{
+#define BUFFER_SIZE 1000
+ char buffer[BUFFER_SIZE];
+ int i, numFields, dataSize;
+ int type = 0;
+ char c;
+ unsigned char *dataBuffer;
+
+ dataBuffer = Tcl_GetByteArrayFromObj(dataPtr, &dataSize);
+
+ /*
+ * Read 4 space-separated fields from the string, ignoring
+ * comments (any line that starts with "#").
+ */
+
+ if (dataSize-- < 1) {
+ return 0;
+ }
+ c = (char) (*dataBuffer++);
+ i = 0;
+ for (numFields = 0; numFields < 4; numFields++) {
+ /*
+ * Skip comments and white space.
+ */
+
+ while (1) {
+ while (isspace(UCHAR(c))) {
+ if (dataSize-- < 1) {
+ return 0;
+ }
+ c = (char) (*dataBuffer++);
+ }
+ if (c != '#') {
+ break;
+ }
+ do {
+ if (dataSize-- < 1) {
+ return 0;
+ }
+ c = (char) (*dataBuffer++);
+ } 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 (dataSize-- < 1) {
+ goto done;
+ }
+ c = (char) (*dataBuffer++);
+ }
+ 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;
+ }
+ if (dataBufferPtr != NULL) {
+ *dataBufferPtr = dataBuffer;
+ *dataSizePtr = dataSize;
+ }
+ return type;
+}