f565d80ff5
Add cropping and scaling to wl_surface. Add a global factory interface wl_scaler, which creates wl_scaler_surface objects tied to a given wl_surface. The wl_scaler_surface object can be used to set a cropping and scaling transformation to change how a wl_buffer maps to wl_surface contents. Changes in v2: Take into account buffer_transform and buffer_scale, and try to explain more clearly how the coordinate transformations work and what their order is. Add, that crop and scale state is double-buffered. Explain missing dst_x, dst_y. Clarify that undefined content still is some content, but NULL buffer implies no content nor size. Changes in v3: Disallow zero values for dst_width and dst_height. Open issues: Should this be a separate interface like here, or just a wl_surface request? If we keep this as a separate interface, rename wl_surface_scaler to wl_viewport.