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

LKeene lionel.keene at gmail.com
Fri Mar 20 14:47:02 EDT 2009

Okay, I just tried the method outlined here:

On my Windows XP box it runs on both Microsoft's runtime as well as Mono
2.2. Performance seems good. I have to fiddle a bit more and see how setting
the DoubleBuffered() property affects things, but generally this is very


Stifu wrote:
> I haven't yet, but I plan to. I want to replace my unsafe FastBitmap class
> with it, so my app can be fully managed and get a little speed boost.
> However, the good thing about the FastBitmap class implementation was that
> it was handled pretty much exactly like the Bitmap one... Not sure if it
> can be done with the pointerless method, at least not as is, apparently,
> because I had a quick look at the class, and it had no SetPixel or
> GetPixel methods.
> LKeene wrote:
>> Stifu,
>> 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...
>> -L
>> 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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