h6. [[SpriteExtend]] h6(. » [[SpriteExtend SWI Calls|SWI Calls]] h6((. » JPEG_PlotTransformed h2. JPEG_PlotTransformed h5. (SWI &49984) |_<^{width:4em}. Entry | | |<^. R0 |<^. Pointer to JPEG image in memory | |/7<^. R1 |<^. Flags: | |<^. Bit 0: R2 is pointer to destination coordinates, else pointer to matrix | |<^. Bit 1: Dither output | |<^. Bit 2: Use full error diffused dithering | |<^. Bit 4: Use colour mapping | |<^. Bits 5-12: Translucency (0 = opaque, 255 = 1/256 visibility) | |<^. Other bits reserved, should be zero | |<^. R2 |<^. Pointer to coordinate block or [[Transformation Matrix|matrix]], as defined by R0 | |<^. R3 |<^. Length of data (bytes) | |<^. R4 |<^. Pointer to [[Colour Mapping Descriptor]], if relevant | |_<^{width:4em}. Exit | | |<^. - |<^. All registers preserved | h4. Use This call is used to plot a transformed JPEG image to screen. h4. Notes If R1 bit 0 is set, R2 is treated as a pointer to a Draw module [[Transformation Matrix]] describing the transform to apply to the image. If bit 0 is clear then R2 is treated as a pointer to a block giving the screen coordinates of a parallelogram to transform the image into: |_<^{width:4em}. Word |_<^. Value | |<^. 0 |<^. X0 coordinate, in 1/256th OS units | |<^. 1 |<^. Y0 coordinate, in 1/256th OS units | |<^. 2 |<^. X1 coordinate, in 1/256th OS units | |<^. 3 |<^. Y1 coordinate, in 1/256th OS units | |<^. 4 |<^. X2 coordinate, in 1/256th OS units | |<^. 5 |<^. Y2 coordinate, in 1/256th OS units | |<^. 6 |<^. X3 coordinate, in 1/256th OS units | |<^. 7 |<^. Y3 coordinate, in 1/256th OS units | Note that the default version of SpriteExtend supplied with RISC OS 5 does not support the plotting of transformed JPEGs. However it will perform a scaled plot if it detects that the transformation can be reduced to a set of scale factors compatible with [[JPEG_PlotScaled]]. h4. See also * [[JPEG_PlotFileTransformed]] * [[Transformation Matrix]]