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Use even stride when saving odd sized .pcx files

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This commit is contained in:
wiredfool 2014-03-03 23:03:36 -08:00
parent a3371ee9fe
commit 89cb3c7e85
2 changed files with 104 additions and 55 deletions
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10
PIL/PcxImagePlugin.py
View File

@ -134,6 +134,16 @@ def _save(im, fp, filename, check=0):
# bytes per plane
stride = (im.size[0] * bits + 7) // 8
# stride should be even
stride = stride + (stride % 2)
# Stride needs to be kept in sync with the PcxEncode.c version.
# Ideally it should be passed in in the state, but the bytes value
# gets overwritten.
if Image.DEBUG:
print ("PcxImagePlugin._save: xwidth: %d, bits: %d, stride: %d" % (
im.size[0], bits, stride))
# under windows, we could determine the current screen size with
# "Image.core.display_mode()[1]", but I think that's overkill...

149
libImaging/PcxEncode.c
View File

@ -26,6 +26,12 @@ ImagingPcxEncode(Imaging im, ImagingCodecState state, UINT8* buf, int bytes)
{
UINT8* ptr;
int this;
int bytes_per_line = 0;
int padding = 0;
int stride = 0;
int bpp = 0;
int planes = 1;
int i;
ptr = buf;
@ -35,12 +41,25 @@ ImagingPcxEncode(Imaging im, ImagingCodecState state, UINT8* buf, int bytes)
state->errcode = IMAGING_CODEC_END;
return 0;
}
state->bytes = (state->xsize*state->bits + 7) / 8;
state->state = FETCH;
}
bpp = state->bits;
if (state->bits == 24){
planes = 3;
bpp = 8;
}
bytes_per_line = (state->xsize*bpp + 7) / 8;
/* The stride here needs to be kept in sync with the version in
PcxImagePlugin.py. If it's not, the header and the body of the
image will be out of sync and bad things will happen on decode.
*/
stride = bytes_per_line + (bytes_per_line % 2);
padding = stride - bytes_per_line;
for (;;) {
switch (state->state) {
@ -72,74 +91,94 @@ ImagingPcxEncode(Imaging im, ImagingCodecState state, UINT8* buf, int bytes)
/* when we arrive here, "count" contains the number of
bytes having the value of "LAST" that we've already
seen */
while (state->x < planes * bytes_per_line) {
/* If we're encoding an odd width file, and we've
got more than one plane, we need to pad each
color row with padding bytes at the end. Since
The pixels are stored RRRRRGGGGGBBBBB, so we need
to have the padding be RRRRRPGGGGGPBBBBBP. Hence
the double loop
*/
while (state->x % bytes_per_line) {
while (state->x < state->bytes) {
if (state->count == 63) {
/* this run is full; flush it */
if (bytes < 2)
return ptr - buf;
*ptr++ = 0xff;
*ptr++ = state->LAST;
bytes -= 2;
state->count = 0;
}
this = state->buffer[state->x];
if (this == state->LAST) {
/* extend the current run */
state->x++;
state->count++;
} else {
/* start a new run */
if (state->count == 1 && (state->LAST < 0xc0)) {
if (bytes < 1) {
if (state->count == 63) {
/* this run is full; flush it */
if (bytes < 2)
return ptr - buf;
}
*ptr++ = 0xff;
*ptr++ = state->LAST;
bytes--;
bytes -= 2;
state->count = 0;
}
this = state->buffer[state->x];
if (this == state->LAST) {
/* extend the current run */
state->x++;
state->count++;
} else {
if (state->count > 0) {
if (bytes < 2) {
/* start a new run */
if (state->count == 1 && (state->LAST < 0xc0)) {
if (bytes < 1) {
return ptr - buf;
}
*ptr++ = 0xc0 | state->count;
*ptr++ = state->LAST;
bytes -= 2;
bytes--;
} else {
if (state->count > 0) {
if (bytes < 2) {
return ptr - buf;
}
*ptr++ = 0xc0 | state->count;
*ptr++ = state->LAST;
bytes -= 2;
}
}
state->LAST = this;
state->count = 1;
state->x++;
}
state->LAST = this;
state->count = 1;
state->x++;
}
}
/* end of line; flush the current run */
if (state->count == 1 && (state->LAST < 0xc0)) {
if (bytes < 1) {
return ptr - buf;
}
*ptr++ = state->LAST;
bytes--;
} else {
if (state->count > 0) {
if (bytes < 2) {
/* end of line; flush the current run */
if (state->count == 1 && (state->LAST < 0xc0)) {
if (bytes < 1 + padding) {
return ptr - buf;
}
*ptr++ = 0xc0 | state->count;
*ptr++ = state->LAST;
bytes -= 2;
bytes--;
} else {
if (state->count > 0) {
if (bytes < 2 + padding) {
return ptr - buf;
}
*ptr++ = 0xc0 | state->count;
*ptr++ = state->LAST;
bytes -= 2;
}
}
if (bytes < padding) {
return ptr - buf;
}
/* add the padding */
for (i=0;i<padding;i++){
*ptr++=0;
bytes--;
}
/* reset for the next color plane. */
if (state->x < planes * bytes_per_line) {
state->count = 1;
state->LAST = state->buffer[state->x];
state->x++;
}
}
/* read next line */
state->state = FETCH;
break;