[Qgis-developer] error for QGIS tutorials in python - adding rasters to canvas

[Martin Dobias]

2008/1/24 Peter Ersts <ersts at amnh.org>:
>
> in 0.9.2, the abstracted draw process per pixel is:
> For gray scale or RGB images
> Read data from band -> Check NoDataValue -> Get transparency level ->
> Stretch -> Invert (if necessary) -> Display
> For paletted, pseudo color, for custom color maps
> Read data from band -> Check NoDataValue -> Get transparency level ->
> Shade(color) -> Invert (if necessary) -> Display

Thanks for the clarifications, Pete!
This helped a lot.
I'm wondering about the difference between raster shaders and contrast
enhancements... is the difference just semantic that shaders are used
for grayscale/RGB images and contrast enhancements for
palleted/pseudocolor images?

Martin