BitmapLayer
Layer that displays a bitmap image.
BitmapLayer is a Layer subtype that draws a GBitmap within its frame. It uses an alignment property to specify how to position the bitmap image within its frame. Optionally, when the background color is not GColorClear, it draws a solid background color behind the bitmap image, filling areas of the frame that are not covered by the bitmap image. Lastly, using the compositing mode property of the BitmapLayer, determines the way the bitmap image is drawn on top of what is underneath it (either the background color, or the layers beneath it).
Inside the Implementation
The implementation of BitmapLayer is fairly straightforward and relies heavily on the functionality as exposed by the core drawing functions (see Drawing Primitives). BitmapLayer's drawing callback uses graphics_draw_bitmap_in_rect() to perform the actual drawing of the GBitmap. It uses grect_align() to perform the layout of the image and it uses graphics_fill_rect() to draw the background plane.
Function
Creates a new bitmap layer on the heap and initalizes it the default values.
Bitmap:
NULL(none)Background color: GColorClear
Compositing mode: GCompOpAssign
Clips:
true
Returns
A pointer to the BitmapLayer. NULL if the BitmapLayer could not be created
Destroys a window previously created by bitmap_layer_create.
Gets the "root" Layer of the bitmap layer, which is the parent for the sub- layers used for its implementation.
Parameters
- bitmap_layer
Pointer to the BitmapLayer for which to get the "root" Layer
Returns
The "root" Layer of the bitmap layer.
Gets the pointer to the bitmap image that the BitmapLayer is using.
Parameters
- bitmap_layer
The BitmapLayer for which to get the bitmap image
Returns
A pointer to the bitmap image that the BitmapLayer is using
Sets the bitmap onto the BitmapLayer. The bitmap is set by reference (no deep copy), thus the caller of this function has to make sure the bitmap is kept in memory.
The bitmap layer is automatically marked dirty after this operation.
Parameters
- bitmap_layer
The BitmapLayer for which to set the bitmap image
- bitmap
The new GBitmap to set onto the BitmapLayer
Sets the alignment of the image to draw with in frame of the BitmapLayer. The aligment parameter specifies which edges of the bitmap should overlap with the frame of the BitmapLayer. If the bitmap is smaller than the frame of the BitmapLayer, the background is filled with the background color.
The bitmap layer is automatically marked dirty after this operation.
Parameters
- bitmap_layer
The BitmapLayer for which to set the aligment
- alignment
The new alignment for the image inside the BitmapLayer
Sets the background color of bounding box that will be drawn behind the image of the BitmapLayer.
The bitmap layer is automatically marked dirty after this operation.
Parameters
- bitmap_layer
The BitmapLayer for which to set the background color
- color
The new GColor to set the background to
Sets the compositing mode of how the bitmap image is composited onto the BitmapLayer's background plane, or how it is composited onto what has been drawn beneath the BitmapLayer.
The compositing mode only affects the drawing of the bitmap and not the drawing of the background color.
For Aplite, there is no notion of "transparency" in the graphics system. However, the effect of transparency can be created by masking and using compositing modes.
For Basalt, when drawing GBitmap images, GCompOpSet will be required to apply any transparency.
The bitmap layer is automatically marked dirty after this operation.
Parameters
- bitmap_layer
The BitmapLayer for which to set the compositing mode
- mode
The compositing mode to set
See Also
GCompOpTypedef
Getting Help
Do you have questions about the Pebble SDK?
Do you need some help understanding something on this page?
You can either take advantage of our awesome developer community and check out the SDK Help forums, or you can send us a message through the website!