GTKD Cairo get pixel color

[Mike Wey via Digitalmars-d-learn]

On 01/04/2016 09:13 PM, TheDGuy wrote:
> On Monday, 4 January 2016 at 19:27:48 UTC, Mike Wey wrote:
>> I think you are looking for something like this.
>>
>> Context.getTarget will get you the surface the Context is drawing to,
>> this most likely isn't a ImageSurface.
>> So you will need to create an pixbuf from the returned surface, with
>> the Pixbuf you can then get the raw pixel data using
>> getPixelsWithLength().
>>
>> ```
>> import gdk.Pixbuf;
>>
>> bool drawCallback(Scoped!Context cr, Widget widget)
>> {
>>     GtkAllocation size;
>>     Pixbuf surafce;
>>
>>     getAllocation(size);
>>
>>     //Draw something;
>>
>>     surface = getFromSurface(cr.getTarget(), 0, 0, size.width,
>> size.height);
>>
>>     ubyte[] data = cast(ubyte[])surface.getPixelsWithLength();
>>
>>     //Do somthing with data.
>>
>>     return true;
>> }
>> ```
>>
>> getPixelsWithLength has the wrong return type, which will probably be
>> fixed some time.
>
> Thank you very much! But surface.getPixelsWithLength() only gives me an
> array with 16 fields (with a 256x256 DrawingArea)?
>
> I also tried to save the Pixbuf with:
>
> string[] options = ["quality"];
> string[] opval = ["100"];
> surface.savev("C:\\Users\\Standardbenutzer\\Desktop\test.jpeg", "jpeg",
> options, opval);
>
> but i found absolutely NOTHING about the options or the option values i
> have to set, therefore i get an invalid argument exception :(

I don't have any issues with either getPixelsWithLength and savev.
for the savev call there is an missing \ just before test.jpg, but that 
might be a copy and paste error?

For the options that are available for savev the documentation of 
GDK-PixBuff lists the few available options.
https://developer.gnome.org/gdk-pixbuf/unstable/gdk-pixbuf-File-saving.html#gdk-pixbuf-save

Although i'm on Linux so that might make an difference.

-- 
Mike Wey