See vips_image_pipelinev(). Operations can hint to the VIPS image IO
system about the kind of demand geometry they prefer.
These demand styles are given below in order of increasing
restrictiveness. When demanding output from a pipeline,
vips_image_generate()
will use the most restrictive of the styles requested by the operations
in the pipeline.
#VIPS_DEMAND_STYLE_THINSTRIP --- This operation would like to output strips
the width of the image and a few pels high. This is option suitable for
point-to-point operations, such as those in the arithmetic package.
This option is only efficient for cases where each output pel depends
upon the pel in the corresponding position in the input image.
#VIPS_DEMAND_STYLE_FATSTRIP --- This operation would like to output strips
the width of the image and as high as possible. This option is suitable
for area operations which do not violently transform coordinates, such
as vips_conv().
#VIPS_DEMAND_STYLE_SMALLTILE --- This is the most general demand format.
Output is demanded in small (around 100x100 pel) sections. This style works
reasonably efficiently, even for bizzare operations like 45 degree rotate.
#VIPS_DEMAND_STYLE_ANY --- This image is not being demand-read from a disc
file (even indirectly) so any demand style is OK. It's used for things like
vips_black() where the pixels are calculated.
See vips_image_pipelinev(). Operations can hint to the VIPS image IO system about the kind of demand geometry they prefer.
These demand styles are given below in order of increasing restrictiveness. When demanding output from a pipeline, vips_image_generate() will use the most restrictive of the styles requested by the operations in the pipeline.
#VIPS_DEMAND_STYLE_THINSTRIP --- This operation would like to output strips the width of the image and a few pels high. This is option suitable for point-to-point operations, such as those in the arithmetic package.
This option is only efficient for cases where each output pel depends upon the pel in the corresponding position in the input image.
#VIPS_DEMAND_STYLE_FATSTRIP --- This operation would like to output strips the width of the image and as high as possible. This option is suitable for area operations which do not violently transform coordinates, such as vips_conv().
#VIPS_DEMAND_STYLE_SMALLTILE --- This is the most general demand format. Output is demanded in small (around 100x100 pel) sections. This style works reasonably efficiently, even for bizzare operations like 45 degree rotate.
#VIPS_DEMAND_STYLE_ANY --- This image is not being demand-read from a disc file (even indirectly) so any demand style is OK. It's used for things like vips_black() where the pixels are calculated.
See also: vips_image_pipelinev().