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[cairo-pdf-surface] Do not bitswap big-endian A1 masks.

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Pixman stores the bits A1 surfaces in native byte order, PDF stores
A1 masks in MSb - so only perform swapping for little-endian machines.

Note this also removes the extraneous packing as per the PDF spec 4.8.2:
"Byte boundaries are ignored, except that each row of sample data must
begin on a byte boundary. If the number of data bits per row is not a
multiple of 8, the end of the row is padded with extra bits to fill out
the last byte."
This commit is contained in:
Chris Wilson 2008-04-03 14:53:17 +01:00
parent 7901eb29ef
commit 6101dc3e93
1 changed files with 7 additions and 23 deletions
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30
src/cairo-pdf-surface.c
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@ -1250,7 +1250,6 @@ _cairo_pdf_surface_emit_smask (cairo_pdf_surface_t *surface,
int i, x, y;
cairo_bool_t opaque;
uint8_t a;
int src_bit, dst_bit;
/* This is the only image format we support, which simplifies things. */
assert (image->format == CAIRO_FORMAT_ARGB32 ||
@ -1260,11 +1259,7 @@ _cairo_pdf_surface_emit_smask (cairo_pdf_surface_t *surface,
stream_ret->id = 0;
if (image->format == CAIRO_FORMAT_A1) {
/* We allocate using slightly different math so that we can get
* the overflow checking from _cairo_malloc_ab, but alpha_size
* needs to be the correct size for emitting the data in the PDF.
*/
alpha_size = (image->width*image->height + 7) / 8;
alpha_size = (image->width + 7) / 8 * image->height;
alpha = _cairo_malloc_ab ((image->width+7) / 8, image->height);
} else {
alpha_size = image->height * image->width;
@ -1278,8 +1273,6 @@ _cairo_pdf_surface_emit_smask (cairo_pdf_surface_t *surface,
opaque = TRUE;
i = 0;
src_bit = 0;
dst_bit = 7;
for (y = 0; y < image->height; y++) {
if (image->format == CAIRO_FORMAT_ARGB32) {
pixel32 = (uint32_t *) (image->data + y * image->stride);
@ -1302,21 +1295,12 @@ _cairo_pdf_surface_emit_smask (cairo_pdf_surface_t *surface,
} else { /* image->format == CAIRO_FORMAT_A1 */
pixel8 = (uint8_t *) (image->data + y * image->stride);
for (x = 0; x < image->width; x++, pixel8++) {
if (dst_bit == 7)
alpha[i] = 0;
if ((*pixel8 >> src_bit) & 1) {
opaque = FALSE;
alpha[i] |= (1 << dst_bit);
}
if (++src_bit > 7) {
src_bit = 0;
pixel8++;
}
if (--dst_bit < 0) {
dst_bit = 7;
i++;
}
for (x = 0; x < (image->width + 7) / 8; x++, pixel8++) {
a = *pixel8;
a = CAIRO_BITSWAP8_IF_LITTLE_ENDIAN (a);
alpha[i++] = a;
if (a != 0xff)
opaque = FALSE;
}
}
}