[fpc-pascal] Why is FPImage dog slow in reading jpeg's?
nc-gaertnma at netcologne.de
Mon May 30 17:05:57 CEST 2011
Tomas Hajny <XHajT03 at hajny.biz> hat am 30. Mai 2011 um 16:50 geschrieben:
> On Mon, May 30, 2011 16:16, michael.vancanneyt at wisa.be wrote:
> > Try the following code:
> > Img:=TFPMemoryImage.Create(0,0);
> > Img.UsePalette:=False;
> > Img.loadFromFile(FileList[i]);
> > That should work much faster. The reason is probably that the default
> > image
> > created by the reader uses a palette, which is of course dog slow when
> > reading
> > large images.
> Interesting. What is supposed to be a "large image"? I ask because the
> original post mentioned 35 kB and 65 kB (and indirectly also dimensions
> around 600x400 if I understand the program output correctly) which I
> certainly wouldn't consider as "large" (and the mentioned time necessary
> for reading it surely not appropriate regardless of using palette or not).
> I guess that some optimization may be reasonable because such pictures
> could be loaded and displayed (including conversion from true colour to
> 256 colours palette) faster even on a 486 machine...
Is there any size, where a palette image is fast?
I think this is a newbie trap and the default for UsePalette should be changed.
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