ScrollWindowRaster

Scrolls the content of the rectangle

Declaration

Source position: intuition.pas line 3593

Arguments

Description

Calls ScrollRasterBF(), which moves the bits in the raster by (dx,dy) towards (0,0) The space vacated is filled by calling EraseRect().

Note: that vacated space is not considered damage! The scroll operation is limited to the rectangle defined by (xmin,ymin)-(xmax,ymax). Bits outside will not be affected. If (xmax,ymax) is outside the rastport then use the lower right corner of the rastport.

If a window is partly obscured, then it is possible for ScrollWindowRaster() to scroll some of the obscured area into view. If the window is simple-refresh, then the formerly obscured area is damage, and the application needs to repair it. If Intuition detects damage as a result of ScrollWindowRaster(), it will send an IDCMP_REFRESHWINDOW event to the application's window. This handling of damage is the principal reason ScrollWindowRaster() is preferred to ScrollRaster() and ScrollRasterBF().

Note: This call uses ScrollRasterBF(), which calls EraseRect() when clearing the newly exposed area. This allows use of a custom layer backfill hook.

Important: boopsi gadgets should use ScrollRaster() or ScrollRasterBF() directly! Never call ScrollWindowRaster() from inside a boopsi gadget's method handler. Note that Intuition will detect and handle damage caused by such use of ScrollRaster() or ScrollRasterBF(), for gadgets with the GMORE_SCROLLRASTER property.

VERY IMPORTANT: if you have any gadgets in your simple-refresh window with the GMORE_SCROLLRASTER property, you must use ScrollWindowRaster() instead of ScrollRaster() or ScrollRasterBF(). Handling of gadget scroll damage is incompatible with continued use of these graphics functions in an Intuition window. NB: If you're using a gadget class whose source code you do not control, that class might be using GMORE_SCROLLRASTER or might start to in a future version. For that reason, you should use ScrollWindowRaster() if you are using any such gadgets.

See also