[Mono-list] LockBits() on Mono 2.2?

LKeene lionel.keene at gmail.com
Fri Mar 20 13:36:41 EDT 2009

have you actually tried the "Fast Pointerless Image Pocessing" method on
CodeProject? I'm implementing it right now and praying there are no issues.
If I can't do fast pixel drawing it's a showstopper for sure. I want this to
work so badly...


Stifu wrote:
> Mono being faster than .NET with SetPixel must have been on a particular
> case... I have found a huge performance issue with Mono and Get/SetPixel()
> in a particular situation, making Mono crawl... Something instantaneous
> with .NET can easily take 10 seconds with Mono (the perf hit is
> exponential, too).
> I couldn't make a reduced test case for that one either yet...
> But hey, that aside, I've been happy with Mono too. :p
> Dan Shryock wrote:
>> On Fri, Mar 20, 2009 at 8:40 AM, LKeene <lionel.keene at gmail.com> wrote:
>>> I actually intend to use it to draw to a memory bitmap pixel-by-pixel,
>>> rather
>>> than calling SetPixel() each time. Apparently that would be extremely
>>> slow
>>> form what I've read online. The only alternative to Set/GetPixel() seems
>>> to
>>> be declaring an unsafe block and using LockBits(). I'll try to test the
>>> mono
>>> LockBits() implementation today, but assuming that there is indeed a
>>> bug,
>>> does anyone have any other ideas of how to accomplish drawing to a
>>> memory
>>> Bitmap other than SetPixel()? I have a precomputed "Color[,]" that
>>> specifies
>>> the pixels colors.
>> In a recent project, I had no troubles working with lockbits on Mono
>> 1.9 on linux.
>> In the past, using some older version of Mono (probably 1.1.x or 1.2.x) I
>> had
>> encountered few troubles working with lockbits but they have been
>> resolved in
>> newer Mono releases.
>> Another thing that I noticed is that calling SetPixel repeatedly on
>> Microsoft's
>> .NET is much slower than calling SetPixel repeatedly on Mono (though
>> lockbits
>> was still faster on both).
>> HTH
>> Dan
>> _______________________________________________
>> Mono-list maillist  -  Mono-list at lists.ximian.com
>> http://lists.ximian.com/mailman/listinfo/mono-list

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