[cairo] Direct manipulation and write to PNG
behdad at behdad.org
Mon Jul 9 12:23:59 PDT 2012
On 07/09/2012 03:16 PM, Carlos López González wrote:
> Can anyone help me to let me know what I'm doing wrong?
The ARGB32 format docs say:
* @CAIRO_FORMAT_ARGB32: each pixel is a 32-bit quantity, with
* alpha in the upper 8 bits, then red, then green, then blue.
* The 32-bit quantities are stored native-endian. Pre-multiplied
* alpha is used. (That is, 50% transparent red is 0x80800000,
* not 0x80ff0000.) (Since 1.0)
Which means, on a little-endian system, the in-memory layout is BGRA. But you
are assuming that it is ARGB in memory.
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