[Mono-winforms-list] [Patch] Invalidate non visible areas in scrolling

[Geoff Norton]

Jon,

   You implemented this as:

                                 if (bmp_g == null) {
                                         bmp = new Bitmap (1, 1,  
System.Drawing.Imaging.PixelFormat.Format32bppArgb);
                                         bmp_g = Graphics.FromImage  
(bmp);
                                 }

We should likely switch this to

if (bmp_g == null) {
	bmp_g = Graphics.FromHwnd (IntPtr.Zero);
}

(and rename bmp_g to root_g or some such).

Our implementation currently wont matter for this for things like dpi;  
but device independent scaling int he future will likely work better  
in the latter case.

Thoughts?

-g

ps> I just commited the support today for mac/x11 support of that Hwnd  
case

On 21-Jan-08, at 8:25 PM, Jonathan Pobst wrote:

> I just added a public property called Hwnd.GraphicsContext that is a
> cached Graphics we keep around for measuring and such.  If you don't
> need a specific Graphics, you can just use this one.
>
> Jon
>
>
> Carlos Alberto Cortez wrote:
>> Hey Chris,
>>
>> Attached is an updated patch that basically incorporates all the  
>> things
>> you mentioned in your last mail:
>>
>> * Determines the visible rectangle, and intersects it with the  
>> required
>> area (this is, we copy only the visible area).
>> 	- First by determining the visible area based on its size and its
>> parents.
>> 	- Second, by looking for toplevel windows that intersect the window,
>> and excluding that area.
>>
>> * Then compute the destination rectangle, by applying the
>> XAmount/YAmount values and intersecting it with the area passed to
>> ScrollWindow (thus we clip it as needed). This is the way Gdk does  
>> it.
>>
>> * Finally, exclude the destination rectangle from the total requested
>> area, and pass it to AddExpose method.
>>
>> With this patch everyting is working as expected, but I have some
>> issues:
>>
>> * Region needs a Graphics instance to return its Bounds, which  
>> *could*
>> be expensive.
>> * After taking a look at the way scrolling is done in Gdk, it *seems*
>> that the Region implementation lack some of the functionality we need
>> (like, returning in a simple operation the Rectangles describing the
>> region).
>>
>> Comments?
>>
>> Carlos.
>>
>>
>> ------------------------------------------------------------------------
>>
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