cairo_draw_from_gl


Description:


public void cairo_draw_from_gl (Context cr, Surface surface, int source, int source_type, int buffer_scale, int x, int y, int width, int height)

This is the main way to draw GL content in GTK.

It takes a render buffer ID (source_type == GL_RENDERBUFFER) or a texture id (source_type == GL_TEXTURE) and draws it onto cr with an OVER operation, respecting the current clip. The top left corner of the rectangle specified by x, y, width and height will be drawn at the current (0,0) position of the cairo_t.

This will work for *all* cairo_t, as long as surface is realized, but the fallback implementation that reads back the pixels from the buffer may be used in the general case. In the case of direct drawing to a surface with no special effects applied to cr it will however use a more efficient approach.

For GL_RENDERBUFFER the code will always fall back to software for buffers with alpha components, so make sure you use GL_TEXTURE if using alpha.

Calling this may change the current GL context.

Parameters:

cr

a cairo context

surface

The surface we're rendering for (not necessarily into)

source

The GL ID of the source buffer

source_type

The type of the source

buffer_scale

The scale-factor that the source buffer is allocated for

x

The source x position in source to start copying from in GL coordinates

y

The source y position in source to start copying from in GL coordinates

width

The width of the region to draw

height

The height of the region to draw


Namespace: Gdk
Package: gtk4