Trait gdk4::prelude::GdkCairoContextExt

source ·

pub trait GdkCairoContextExt {
    unsafe fn draw_from_gl(
        &self,
        surface: &Surface,
        source: i32,
        source_type: i32,
        buffer_scale: i32,
        x: i32,
        y: i32,
        width: i32,
        height: i32
    );
    fn set_source_rgba(&self, rgba: &RGBA);
    fn set_source_pixbuf(&self, pixbuf: &Pixbuf, x: f64, y: f64);
    fn add_rectangle(&self, rectangle: &Rectangle);
    fn add_region(&self, region: &Region);
}

Expand description

Trait containing integration methods with cairo::Context.

Required Methods§

source

unsafe fn draw_from_gl(
    &self,
    surface: &Surface,
    source: i32,
    source_type: i32,
    buffer_scale: i32,
    x: i32,
    y: i32,
    width: i32,
    height: i32
)

Safety

It’s the responsibility of the caller to ensure that source is a valid GL resource. The main way to not 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::Context.

This will work for all cairo::Context, 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.

Deprecated since 4.6

The function is overly complex and produces broken output in various combinations of arguments. If you want to draw with GL textures in GTK, use GLTexture::new(); if you want to use that texture in Cairo, use TextureExtManual::download() to download the data into a Cairo image surface.