On Monday, 4 January 2016 at 23:47:05 UTC, Basile B. wrote:
On Friday, 1 January 2016 at 22:00:04 UTC, TheDGuy wrote:
On Friday, 1 January 2016 at 19:32:40 UTC, Basile B. wrote:
On Wednesday, 30 December 2015 at 23:20:23 UTC, Basile B.
wrote:
On Wednesday, 30 December 2015 at 20:44:44 UTC, TheDGuy
wrote:
Hello,
is there any way to get the pixel color of a single pixel
by x and y coordinates of a context?
render to a png back buffer.
see cairo_image_surface_create_for_data
then you'll be able to access the data and, at the same
time, to blit your buffer to screen.
Actually I was thinking to a user defined buffer type:
struct SurfaceBuffer
{
void* data; // used as param to create the surface
Rgba[] opIndex(size_t index);
Rgba[][] scanline();
}
that you would pass as data in
cairo_image_surface_create_for_data().
But gtk certainly has pitcure classes with the typical
scanline method and that you could use in
cairo_image_surface_create_for_data.
Ahm, i am not quite sure if you and [Mike Wey] talk about the
same thing. And i posted the error message in my last post
when i try to call "cairo_image_surface_create_for_data". I
still don't know where i am able to call the function?
I've not followed the conversation since last time, but you can
have a look at this:
https://github.com/BBasile/kheops/blob/master/src/kheops/bitmap.d#L143
this is how I do with Cairo only (even x11 is not implied since
it's just a bitmap).
Then I can access pixels (for example to make shadows or blurs
etc.) and do vectorial drawings as well with a context for the
bitmap surface.
I tried it like in this C++ example:
http://stackoverflow.com/questions/16785886/get-pixel-value-on-gdkpixbuf-set-pixel-value-with-gdkcairo
surface =
getFromSurface(cr.getTarget(),0,0,size.width,size.height);
int offset = 12*surface.getRowstride() +
12*surface.getNChannels();
auto px = surface.getPixels();
px[offset][0] = 0;
But i get "only one index allowed to index char". So it looks
like there is no 2D array but just a char.
If i try like this:
auto px = surface.getPixels()[offset];
the value of 'px' looks like this in the debugger:
http://www.pic-upload.de/view-29334489/d_value.png.html
