Paths in GTK Part 3 , rendering with paths

Platform
1

As far as I can find it, the 3 part of “Paths in GTK” has not yet been released.

Therefore here is my question:

With which function I can render the following triangle from Part 1:

builder = gsk_path_builder_new ();
gsk_path_builder_move_to (builder, 0, 50);
gsk_path_builder_line_to (builder, 100, 50);
gsk_path_builder_line_to (builder, 50, 0);
gsk_path_builder_close (builder);
path = gsk_path_builder_free_to_path (builder);

So far, I could only use the function gtk_snapshot_append_fill (...)
find. But these then fills the whole area.

2

After some experimentation, I came on it myself.


void graphic_snapshot(GtkSnapshot *snapshot,
                      const GdkRGBA  *foreground,
                      const GdkRGBA  *background,
                      double        width,
                      double        height)
{
        gtk_snapshot_append_color(snapshot,
                                  background,
                                  &GRAPHENE_RECT_INIT (0, 0, width, height));
        double size;
        size = MIN(width,height);
        gtk_snapshot_translate (snapshot, &GRAPHENE_POINT_INIT(0.0,0.0));
        gtk_snapshot_scale (snapshot, size, size);
        GskPathBuilder *builder;
        GskPath *path;
        GskStroke *stroke;
        stroke = gsk_stroke_new(0.01);

        builder = gsk_path_builder_new ();
        gsk_path_builder_move_to (builder, 0.1, 0.1);
        gsk_path_builder_line_to (builder, 0.1, 0.9);
        gsk_path_builder_line_to (builder, 0.9, 0.5);
        gsk_path_builder_close (builder);
        path = gsk_path_builder_free_to_path (builder);

        gtk_snapshot_append_stroke (snapshot, path, stroke, foreground);
        gsk_path_unref(path);
        gsk_stroke_free(stroke);
}

The question that remains for me is now:
Do the parameters always have to be =< 1?

image

3

Because you scaled it?

1 Like
4

You called gtk_snapshot_scale() and normalised the coordinate space in the [0, 1] range (0 = 0, 1 = size) on both axes.