Binary Raster Operations
This section lists the binary raster-operation codes used by the
GetROP2 and
SetROP2 functions. Raster-operation codes define how GDI combines the bits from the
selected pen with the bits in the destination bitmap.
Each raster-operation code represents a Boolean operation in which the values
of the pixels in the selected pen and the destination bitmap are combined.
Following are the two operands used in these operations:
Operand
| Meaning
|
P
| Selected pen
|
D
| Destination bitmap
|
The Boolean operators used in these operations follow:
Operator
| Meaning
|
a
| Bitwise AND
|
n
| Bitwise NOT (inverse)
|
o
| Bitwise OR
|
x
| Bitwise exclusive OR (XOR)
|
All Boolean operations are presented in reverse Polish notation. For example,
the following operation replaces the values of the pixels in the destination
bitmap with a combination of the pixel values of the pen and the selected brush:
DPo
Each raster-operation code is a 32-bit integer whose high-order word is a
Boolean operation index and whose low-order word is the operation code. The 16-bit
operation index is a zero-extended 8-bit value that represents all possible
outcomes resulting from the Boolean operation on two parameters (in this case, the
pen and destination values). For example, the operation indexes for the DPo
and DPan operations are shown in the following list:
The following list outlines the drawing modes and the Boolean operations that
they represent:
Raster operation
| Boolean operation
|
R2_BLACK
| 0
|
R2_COPYPEN
| P
|
R2_MASKNOTPEN
| DPna
|
R2_MASKPEN
| DPa
|
R2_MASKPENNOT
| PDna
|
R2_MERGENOTPEN
| DPno
|
R2_MERGEPEN
| DPo
|
R2_MERGEPENNOT
| PDno
|
R2_NOP
| D
|
R2_NOT
| Dn
|
R2_NOTCOPYPEN
| Pn
|
R2_NOTMASKPEN
| DPan
|
R2_NOTMERGEPEN
| DPon
|
R2_NOTXORPEN
| DPxn
|
R2_WHITE
| -
|
R2_XORPEN
| DPx
|
For a monochrome device, GDI maps the value zero to black and the value 1 to
white. If an application attempts to draw with a black pen on a white
destination by using the available binary raster operations, the following results occur:
Raster operation
| Result
|
R2_BLACK
| Visible black line
|
R2_COPYPEN
| Visible black line
|
R2_MASKNOTPEN
| No visible line
|
R2_MASKPEN
| Visible black line
|
R2_MASKPENNOT
| Visible black line
|
R2_MERGENOTPEN
| No visible line
|
R2_MERGEPEN
| Visible black line
|
R2_MERGEPENNOT
| Visible black line
|
R2_NOP
| No visible line
|
R2_NOT
| Visible black line
|
R2_NOTCOPYPEN
| No visible line
|
R2_NOTMASKPEN
| No visible line
|
R2_NOTMERGEPEN
| Visible black line
|
R2_NOTXORPEN
| Visible black line
|
R2_WHITE
| No visible line
|
R2_XORPEN
| No visible line
|
For a color device, GDI uses RGB values to represent the colors of the pen and
the destination. An RGB color value is a long integer that contains a red, a
green, and a blue color field, each specifying the intensity of the given color.
Intensities range from 0 through 255. The values are packed in the three
low-order bytes of the long integer. The color of a pen is always a solid color, but
the color of the destination may be a mixture of any two or three colors. If
an application attempts to draw with a white pen on a blue destination by using
the available binary raster operations, the following results occur:
Raster operation
| Result
|
R2_BLACK
| Visible black line
|
R2_COPYPEN
| Visible white line
|
R2_MASKNOTPEN
| Visible black line
|
R2_MASKPEN
| Invisible blue line
|
R2_MASKPENNOT
| Visible red/green line
|
R2_MERGENOTPEN
| Invisible blue line
|
R2_MERGEPEN
| Visible white line
|
R2_MERGEPENNOT
| Visible white line
|
R2_NOP
| Invisible blue line
|
R2_NOT
| Visible red/green line
|
R2_NOTCOPYPEN
| Visible black line
|
R2_NOTMASKPEN
| Visible red/green line
|
R2_NOTMERGEPEN
| Visible black line
|
R2_NOTXORPEN
| Invisible blue line
|
R2_WHITE
| Visible white line
|
R2_XORPEN
| Visible red/green line
|
- Software for developers
-
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- More information resources
-
MegaDetailed.Net
Unix Manual Pages
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-
Amazon Categories Database
Browse Nodes Database
