NAME

tag_image_transform - Associate a callback with a transformation chain slot

SYNOPSIS

nil
tag_image_transform( vid:dst, number:slot_mask, function:callback )

DESCRIPTION

This function can be used to associate a callback function with the last set transformation for one or several slots (using the slot_mask). When the specified transform has completed, an event will be added to the outgoing queue and activated when dequeued.

NOTES

1: Only MASK_POSITION , MASK_ORIENTATION , MASK_SCALE and MASK_OPACITY are valid slot_mask values and the engine will warn if other values are provided.
2: If there is no transformation queued in the specified slot, no internal state change will be performed.
3: Depending on synchronization and event- queue polling mechanism, the actual event fire can be off by one or more ticks (unlikely).
4: This should be used sparringly as each transformation completion will emit an event.
5: The callback allocation will not persist across transformation cycles defined via image_transform_cycle .
6: This can also be used as a rough timer.
7: Be careful when combining tagged transforms with calls to
instant_image_transform as callbacks might be masked or lose their chained pacing. Test tagged transforms for strong reactions when being omitted or stormed.

EXAMPLE

function tag_image_transform0()
      local vid = fill_surface(64, 64, 0, 255, 0);
      show_image(vid);
      move_image(vid, 50, 50, 50);
      move_image(vid, 100, 100, 100);
      tag_image_transform(vid, MASK_POSITION, function()
            print("move 2 reached", CLOCK);
      end);
      rotate_image(vid, 45, 75);
      tag_image_transform(vid, MASK_ORIENTATION, function()
            print("rotate 1 reached", CLOCK);
      end);
      blend_image(vid, 0.1, 100);
      tag_image_transform(vid, MASK_OPACITY, function()
            print("blend 1 reached", CLOCK);
      end);
      blend_image(vid, 0.5, 50);
      tag_image_transform(vid, MASK_OPACITY, function()
            print("blend 2 reached", CLOCK);
      end);
end

MISUSE

function tag_image_transform0()
      tag_image_transform(BADID, 0, tag_image_transform);
end

MISUSE

function tag_image_transform1()
      tag_image_transform(alloc_surface(64, 64), tag_image_transform);
end