Glossary
FM4, S6E2DH/S6E2DF/S6E2D5/S6E2D3 Series, 32-Bit Microcontroller, Graphic Driver User Manual, Doc. No. 002-04387 Rev. *A
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Name
Description
Simple Transformation
We talk about simple transformation if an image source is translated, mirrored and/or
rotated by a multiple of 90°. Nearly all 2D core components can do simple
transformation while reading an image. For instance a display controller can directly
show horizontal mirrored images.
Note:
90°and 270°rotations result in a higher memory read rate. Especially for
high resolution displays it is not recommended to use this feature.
Compressed images cannot be used with simple transformations.
Stride
The amount of bytes that must be skipped over to get from one pixel in an image to
the pixel with the same horizontal position in the next line of this image.
Sub-layer
A sub-layer is analog to layers an image that is blended over a background in the
display controller. A sub-layer is always part of a layer. Different to layers it is not
possible to blend overlapping sub-layers together if they share the same layer id. Only
the top most sub-layer image pixel will be read from memory and this color information
will be used for the layer blend operation.
Surface
Surface stands for an memory object describing one or more memory blocks
describing an image. Many 2D Graphics Driver API calls use surface objects for the
functions. See also Surface Overview.
Virtual Address
The Virtual Address stands for an address representing the CPU view of an hardware
address like a register or start of a memory block. In contrast to the Physical Address
this address type cannot be used by 2D Graphics hardware components. See also
Physical Address - Virtual Address.
VRAM
Abbreviation for
V
ideo
R
andom
A
ccess
M
emory. This is a dedicated memory with
short read and write access time that is designed to store and buffer images. The
VRAM can be part of the 2D Graphics hardware block but it is also possible to use
external memory as VRAM.
Window
The term Window is used to describe a software object that keeps all parameters to
push a rectangular image to the display.