[1632447]: Allow the PPM maxval to go up to 65535, to conform with a format

definition change from around 2000 (even if that's a rare format).

2 files changed, 48 insertions, 21 deletions

diff --git a/generic/tkImgPPM.c b/generic/tkImgPPM.c
index edd1b71..d9c06ab 100644
--- a/generic/tkImgPPM.c
+++ b/generic/tkImgPPM.c
@@ -141,7 +141,7 @@ FileReadPPM(
 				 * image being read. */
 {
     int fileWidth, fileHeight, maxIntensity;
-    int nLines, nBytes, h, type, count;
+    int nLines, nBytes, h, type, count, bytesPerChannel = 1;
     unsigned char *pixelPtr;
     Tk_PhotoImageBlock block;
 
@@ -158,12 +158,14 @@ FileReadPPM(
 	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "DIMENSIONS", NULL);
 	return TCL_ERROR;
     }
-    if ((maxIntensity <= 0) || (maxIntensity >= 256)) {
+    if ((maxIntensity <= 0) || (maxIntensity > 0xffff)) {
 	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
 		"PPM image file \"%s\" has bad maximum intensity value %d",
 		fileName, maxIntensity));
 	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "INTENSITY", NULL);
 	return TCL_ERROR;
+    } else if (maxIntensity > 0x00ff) {
+	bytesPerChannel = 2;
     }
 
     if ((srcX + width) > fileWidth) {
@@ -173,20 +175,20 @@ FileReadPPM(
 	height = fileHeight - srcY;
     }
     if ((width <= 0) || (height <= 0)
-	|| (srcX >= fileWidth) || (srcY >= fileHeight)) {
+	    || (srcX >= fileWidth) || (srcY >= fileHeight)) {
 	return TCL_OK;
     }
 
     if (type == PGM) {
-	block.pixelSize = 1;
+	block.pixelSize = 1 * bytesPerChannel;
 	block.offset[0] = 0;
 	block.offset[1] = 0;
 	block.offset[2] = 0;
     } else {
-	block.pixelSize = 3;
+	block.pixelSize = 3 * bytesPerChannel;
 	block.offset[0] = 0;
-	block.offset[1] = 1;
-	block.offset[2] = 2;
+	block.offset[1] = 1 * bytesPerChannel;
+	block.offset[2] = 2 * bytesPerChannel;
     }
     block.offset[3] = 0;
     block.width = width;
@@ -228,12 +230,21 @@ FileReadPPM(
 	    ckfree(pixelPtr);
 	    return TCL_ERROR;
 	}
-	if (maxIntensity != 255) {
+	if (maxIntensity < 0x00ff) {
 	    unsigned char *p;
 
 	    for (p = pixelPtr; count > 0; count--, p++) {
 		*p = (((int) *p) * 255)/maxIntensity;
 	    }
+	} else if (maxIntensity > 0x00ff) {
+	    unsigned char *p;
+	    unsigned int value;
+
+	    for (p = pixelPtr; count > 0; count--, p += 2) {
+		value = ((unsigned int) p[0]) * 256 + ((unsigned int) p[1]);
+		value = value * 255 / maxIntensity;
+		p[0] = p[1] = (unsigned char) value;
+	    }
 	}
 	block.height = nLines;
 	if (Tk_PhotoPutBlock(interp, imageHandle, &block, destX, destY,
@@ -478,7 +489,7 @@ StringReadPPM(
 				 * image being read. */
 {
     int fileWidth, fileHeight, maxIntensity;
-    int nLines, nBytes, h, type, count, dataSize;
+    int nLines, nBytes, h, type, count, dataSize, bytesPerChannel = 2;
     unsigned char *pixelPtr, *dataBuffer;
     Tk_PhotoImageBlock block;
 
@@ -496,12 +507,14 @@ StringReadPPM(
 	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "DIMENSIONS", NULL);
 	return TCL_ERROR;
     }
-    if ((maxIntensity <= 0) || (maxIntensity >= 256)) {
+    if ((maxIntensity <= 0) || (maxIntensity > 0xffff)) {
 	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
 		"PPM image data has bad maximum intensity value %d",
 		maxIntensity));
 	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "INTENSITY", NULL);
 	return TCL_ERROR;
+    } else if (maxIntensity > 0x00ff) {
+	bytesPerChannel = 2;
     }
 
     if ((srcX + width) > fileWidth) {
@@ -516,15 +529,15 @@ StringReadPPM(
     }
 
     if (type == PGM) {
-	block.pixelSize = 1;
+	block.pixelSize = 1 * bytesPerChannel;
 	block.offset[0] = 0;
 	block.offset[1] = 0;
 	block.offset[2] = 0;
     } else {
-	block.pixelSize = 3;
+	block.pixelSize = 3 * bytesPerChannel;
 	block.offset[0] = 0;
-	block.offset[1] = 1;
-	block.offset[2] = 2;
+	block.offset[1] = 1 * bytesPerChannel;
+	block.offset[2] = 2 * bytesPerChannel;
     }
     block.offset[3] = 0;
     block.width = width;
@@ -535,7 +548,7 @@ StringReadPPM(
 	dataSize -= srcY * block.pitch;
     }
 
-    if (maxIntensity == 255) {
+    if (maxIntensity == 0x00ff) {
 	/*
 	 * We have all the data in memory, so write everything in one go.
 	 */
@@ -582,8 +595,19 @@ StringReadPPM(
 	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "TRUNCATED", NULL);
 	    return TCL_ERROR;
 	}
-	for (p=pixelPtr,count=nBytes ; count>0 ; count--,p++,dataBuffer++) {
-	    *p = (((int) *dataBuffer) * 255)/maxIntensity;
+	if (maxIntensity < 0x00ff) {
+	    for (p=pixelPtr,count=nBytes ; count>0 ; count--,p++,dataBuffer++) {
+		*p = (((int) *dataBuffer) * 255)/maxIntensity;
+	    }
+	} else {
+	    unsigned char *p;
+	    unsigned int value;
+
+	    for (p = pixelPtr; count > 0; count--, p += 2) {
+		value = ((unsigned int) p[0]) * 256 + ((unsigned int) p[1]);
+		value = value * 255 / maxIntensity;
+		p[0] = p[1] = (unsigned char) value;
+	    }
 	}
 	dataSize -= nBytes;
 	block.height = nLines;
diff --git a/tests/imgPPM.test b/tests/imgPPM.test
index 456427f..b5955df 100644
--- a/tests/imgPPM.test
+++ b/tests/imgPPM.test
@@ -21,7 +21,7 @@ proc put {file data} {
     puts -nonewline $f $data
     close $f
 }
-
+
 test imgPPM-1.1 {FileReadPPM procedure} -body {
     put test.ppm "P6\n0 256\n255\nabcdef"
     image create photo p1 -file test.ppm
@@ -39,9 +39,9 @@ test imgPPM-1.4 {FileReadPPM procedure} -body {
     image create photo p1 -file test.ppm
 } -returnCodes error -result {PPM image file "test.ppm" has dimension(s) <= 0}
 test imgPPM-1.5 {FileReadPPM procedure} -body {
-    put test.ppm "P6\n10 20\n256\nabcdef"
+    put test.ppm "P6\n10 20\n100000\nabcdef"
     image create photo p1 -file test.ppm
-} -returnCodes error -result {PPM image file "test.ppm" has bad maximum intensity value 256}
+} -returnCodes error -result {PPM image file "test.ppm" has bad maximum intensity value 100000}
 test imgPPM-1.6 {FileReadPPM procedure} -body {
     put test.ppm "P6\n10 20\n0\nabcdef"
     image create photo p1 -file test.ppm
@@ -161,7 +161,7 @@ test imgPPM-4.1 {StringReadPPM procedure, data too short [Bug 1822391]} -body {
 } -cleanup {
     image delete I
 } -returnCodes error -result {truncated PPM data}
-
+
 imageFinish
 
 # cleanup
@@ -169,3 +169,6 @@ catch {file delete test.ppm}
 cleanupTests
 return
 
+# Local Variables:
+# mode: tcl
+# End: