Alignment notes
Source image alignment requirement
The buffer start address and stride byte-alignment requirement for a pixel depends on the specific pixel format and the gcFEATURE_VG_16PIXELS_ALIGNED value (0/1) in the vg_lite_options.h file.
|Image format|Bits per pixel|Start address alignment requirement in bytes|Stride alignment requirement in bytes
|Supported for source image|Supported for destination| |————|————–|——————————————–|—————————————|————————–|————————-| |VG_LITE_INDEX1|1|8B|8B|Yes| | |VG_LITE_INDEX2|2|8B|8B|Yes|| |VG_LITE_INDEX4|4|8B|8B|Yes|| |VG_LITE_INDEX8|8|16B|16B|Yes|| |VG_LITE_A4|4|4B|8B|Yes|| |VG_LITE_A8|8|4B|16B|Yes|Yes| |VG_LITE_L8|8|4B|16B|Yes|Yes| |VG_LITE_ARGB2222 group|8|4B|16B|Yes|Yes| |VG_LITE_RGB565 group|16|4B|32B|Yes|Yes| |VG_LITE_ARGB1555 group|16|4B|32B|Yes|Yes| |VG_LITE_ARGB4444 group|16|4B|32B|Yes|Yes| |VG_LITE_YUY2/UYVY|16|4B|32B|Yes|| |VG_LITE_ARGB8888/XRGB8888 group|32|4B|64B|Yes|Yes| |VG_LITE_ARGB8565/RGB888 group|32|4B|64B|Yes|Yes| |VG_LITE_NV12_TILED|Tile 4x4|Y: 16B
UV: 8B
|Y: 16B
UV: 8B
|Yes|| |VG_LITE_ANV12_TILED|Tile 4x4|Y: 16B
UV: 8B
|Y: 16B
UV: 8B
|Yes|| |VG_LITE_AYUY2_TILED|Tile 4x4|32B|32B|Yes||
VGLite hardware requires the raster image width to be a multiple of 16 pixels for linear gradient and radial gradient operations. This requirement applies to all image formats. Therefore, the user must pad an arbitrary image width to a multiple of 16 pixels for the VGLite linear gradient and radial gradient APIs.
Destination alignment requirement:
For Pixel Engine (PE) destination, the alignment should be 64B for all tiled (4x4) formats.
Alignment may also be limited by the alignment requirements of backend modules such as DC (Display Controller).
Parent topic:vg_lite_buffer_format_t enumeration