formZ SDK | 4.0 Call Back Reference | Renderer
Description
Image display function.
The image display function is the main function of a renderer. It is called by formZ anytime
the rendering on the screen needs to be refreshed. It is always called after the image
init function and before the image finit function. The sub_image argument is only passed as non
NULL for static pixel renderers. If passed as NULL, the renderer is expected to render the entire
image. If it is non NULL, the sub_image rectangle outlines a rectangular portion of the image
to be rendered. It is the responsibility of the renderer to not pass more than
(sub_image->bottom - sub_image->top) number of scanlines to
and to make sure that each scanline is exactly (sub_image->right - sub_image->left) pixels
wide. The sub_image rectangle is, for example, passed in if the Set Image Size option is
checked by the user, or if the renderer is used by the network rendering environment and
is asked to render one or more bands of an image.
If the image init function generated an error, it is passed into the display function.
This gives the display function the opportunity to perform any necessary cleanup because
of the error. The display function is expected to NOT render the image, if an error is
passed in.
Plugin Prototype
fzrt_error_td fz_rndr_cbak_image_disp(
fzrt_int | windex, |
prep_err, | |
subimage ) |
Parameters
windex [Input]
project window index
prep_err [Input]
error code generated by the image init function.
subimage [Input, Optional]
If passed as NULL, the renderer is expected to display the entire image. If non NULL, the rectangle passed in outlines a sub area of the image to be rendered. This parameter is only used for static pixel renderers.
Returns
Error codes
Availability
5.0.0.0
Function Set
Defined in