nanogui: Re: [FIX] add alpha channel into GdDrawImage software handling
Subject:
Re: [FIX] add alpha channel into GdDrawImage software handling
From:
"Greg Haerr" ####@####.####
Date:
10 Mar 2010 05:26:41 -0000
Message-Id: <05bc01cac012$417966e0$6564a8c0@winXP>
> I added software alpha blending routine in GdDrawImage().
Mr Sung Joo -
During the extensive porting of the Sony PSP and new
ABGR framebuffer support, I relooked at the GdDrawImage
code that you have gratefully contributed. There were still
some consistency issues, mostly in documentation, on
exactly the pixel and framebuffer format in use. I have
heavily commented and in some cases rewritten the
alpha channel drawing code, and would like you to
have a look at it, and possibly test on the
SCREEN_PIXTYPEs you tested below. I also added
support for alpha blending in the new ABGR framebuffer
format used in PSP.
When handling images with alpha channel, for now
we always convert to 0xAARRGGBB longword
format, and then possibly reconvert or alpha-blend
from there. All cases, including big and little endian
are handled, but the fastest case, little endian .png
files in MWIMAGE_RGB format, still do more
bit-twiddling than is necessary. I am still looking
into this, but didn't want to change everything
all at once! The cases when converting
to truecolor 3/3/2 or when #define ALPHABLEND 0
are still slow also.
Thanks again for your contributions!
Regards,
Greg
I have tested following case by using "nxview
PNG_transparency_demonstration_2.png".
( only tested little endian. )
SCREEN_PIXTYPE = MWPF_TRUECOLOR0888
SCREEN_PIXTYPE = MWPF_TRUECOLOR888
SCREEN_PIXTYPE = MWPF_TRUECOLOR565
SCREEN_PIXTYPE = MWPF_TRUECOLOR555
SCREEN_PIXTYPE = MWPF_TRUECOLOR8888
Regards
