38.6.9.3 Image Rotation And Mirroring

Image rotation or mirroring is produced by combining pixel and line striding to read image pixels in a different order, as shown in the figure below.

The Configuration tables below show how to configure registers according to image transformation. The following notations are used:

• FPA = original image First Pixel Address
• Xs = original image horizontal number of pixels
• Ys = original image vertical number of pixels
• Ps = original image Pixel size expressed in byte (see Pixel Size Values)
• HXs = floor{(Xs+1)/2} , the rounded half of Xs
• HYs = floor{(Ys+1)/2} , the rounded half of Ys

  Table 38-46. Pixel Size Values

  Input Mode	Ps Value (in bytes)
  12BPP_RGB_444	2
  16BPP_ARGB_4444	2
  16BPP_RGBA_4444	2
  16BPP_RGB_565	2
  16BPP_ARGB_1555	2
  18BPP_RGB_666	4
  18BPP_RGB_666PACKED	3
  19BPP_ARGB_1666	4
  19BPP_ARGB_PACKED	3
  24BPP_RGB_888	4
  24BPP_RGB_888_PACKED	3
  25BPP_ARGB_1888	4
  32BPP_ARGB_8888	4
  32BPP_RGBA_8888	4
  32BPP_AYCBCR	4
  16BPP_YCBCR_MODE0	1
  16BPP_YCBCR_MODE1
  16BPP_YCBCR_MODE2
  16BPP_YCBCR_MODE3
  16BPP_YCBCR_SEMIPLANAR
  16BPP_YCBCR_PLANAR
  12BPP_YCBCR_SEMIPLANAR
  12BPP_YCBCR_PLANAR

  Table 38-47. Rotation Configuration (All Input Modes, All Overlays)

  Rotation Angle	0°	90°	180°	270°
  FBA	FPA	FPA + (Xs-1)*Ps	FPA + (Xs*Ys - 1)*Ps	FPA + Xs*(Ys-1)*Ps
  XSIZE/XMEMSIZE	Xs-1	Ys-1	Xs-1	Ys-1
  YSIZE/YMEMSIZE	Ys-1	Xs-1	Ys-1	Xs-1
  XSTRIDE	0	-((Ys-1)*Xs + 2)*Ps	-2*Ps	Xs*(Ys-1)*Ps
  PSTRIDE	0	(Xs-1)*Ps	-2*Ps	-(Xs+1)*Ps

For rotation transformation in High-End Overlay with YCbCr planar and semi-planar modes, additional registers must be configured, as shown in the following tables.

For mirroring transformation in High-End Overlay with YCbCr planar and semi-planar modes, additional registers have to be configured, as shown in the following tables.