read the pen number value of the pixel at a specified x,y location within a certain RastPort.
Source position: agraphics.pas line 2033
function ReadPixel( |
Rp: PRastPort; |
X: LongInt; |
Y: LongInt |
):LongWord; |
Rp |
|
A pointer to a RastPort structure |
X |
|
X Coordinate to read |
Y |
|
Y Coordinate to read |
The pen number of the pixel at (x,y) is returned. -1 is returned if the pixel cannot be read for some reason.
Combine the bits from each of the bit-planes used to describe a particular RastPort into the pen number selector which that bit combination normally forms for the system hardware selection of pixel color.
|
Change the pen num of one specific pixel in a specified RastPort. |