Table of Contents
Advertisement
Drawing Engine
8.3.3 BitBLT
8.3.3.1
8.3.3.2
8.3.3.3
8.3.3.4
8.3.3.5
There is no need for a dedicated BitBlt unit in the Drawing Engine. The rendering
pipeline described for vector drawing is used as BitBLT unit and already provides
a 1pixel/cycle throughput. For a more detailed understanding please refer to the
dedicated chapter about the rendering pipeline.
Fill
Any rectangle in the framebuffer can be filled with any value. Possible colour
formats are any 8 bpp/16 bpp/32 bpp format. The driver optimizes the fill to get
the full benefit of 32 bit parallel rasterization. In case of the selected colour format
is less than 32 bpp then the driver takes care for the correct alignment and fills
32 bit per clock. This results in 2-4 times larger fill performance for 8 bpp and 16
bpp formats.
Copy
Any rectangle in the framebuffer can be filled with any rectangular data from the
texture input. When the texture input points to the framebuffer then copy from
framebuffer to framebuffer is possible. To avoid copy problems due to
overlapping source and destination areas, the copy start point can be selected
from top left to bottom right. Possible colour formats are any 8 bpp/16 bpp/32
bpp format.
The driver optimizes the copy to get the full benefit of 32 bit parallel rasterization.
In case of the selected colour format is less than 32 bpp then the driver takes care
for the correct alignment and copies 32 bit per clock. This results in 2-4 times
larger copy performance for 8 bpp and 16 bpp formats.
Stretch BitBLT
This is very similar to the normal copy operation. As the copy is done as kind of
texture mapping, the full texture mapping feature set can be used. The user can
select arbitrary scaling ratios in x- and y-direction. Filtering can be enabled
independantly for each axis.
Rotate and scale
This is also very similar to the normal copy operation. As the copy is done as kind
of texture mapping, the full texture mapping feature set can be used. The user
can select arbitrary scaling ratios in x- and y-direction as well as any rotation
angle. Also the user can select independent in x- and y-direction, whether the
scaler use filters or not.
Alpha blending
Alpha blending is one fundamental block in the rendering pipeline. Therefore the
full alpha blend feature set is available also for any BitBLT operation. It is possible
to copy an area and blend it over the destination by using any constant global
alpha value (register value) or by an alpha mask. The alpha mask is part of the
texture data and can be either a per-pixel value together with a pixel colour (aRGB
formats) or can be an alpha only format using a register colour.
Preliminary User's Manual S19203EE1V3UM00
Chapter 8
221
Advertisement
Table of Contents
