special-draw

special-draw is a very simple way to implement advanced graphical effects in your Pebble apps. Some examples of possible modifiers are:

Usage example

static void layer_update_proc(Layer *layer, GContext *ctx) {
    // Draw a rect normally.
    graphics_draw_rect(ctx, GRect(32, 54, 80, 60));

    // Begin a special-draw session.
    GSpecialSession * session =
        graphics_context_begin_special_draw(ctx);

    // Add an opacity modifier...
    graphics_context_special_session_add_modifier(session,
        graphics_special_draw_create_opacity_modifier(GOpacity2));
    // ...and a rotation modifier.
    graphics_context_special_session_add_modifier(session,
        graphics_special_draw_create_rotation_modifier(TRIG_MAX_ANGLE/8));
​
    // Draw a rectangle. This one will be affected by
    //     the special-draw modifiers, the previous one won't.
    graphics_draw_rect(ctx, GRect(38, 60, 80, 60));
​
​    // We're done here.
    graphics_context_end_special_draw(session);
}

Goals

• special-draw should let you use built-in graphics functions.
• special-draw should be easy to extend.
• special-draw should let you chain modifiers.

special-draw is released under the MIT license.

For more information about the app and modifier APIs, see the README.