Windows 3.1 Device Drivers (ddag31qh.hlp) (Table of Contents; Topic list)
ColorInfo
                                                     Up Next Previous
────────────────────────────────────────────────────────────────────────────
 
COLORREF ColorInfo(lpDestDev, dwColorin, lpPColor)
LPPDEVICE lpDestDev;
DWORD dwColorin;
LPPCOLOR lpPColor;
 
The ColorInfo function converts a logical color (an RGB value) to a physical
color ( a physical color value) or converts a physical to a logical color,
depending on the value of the lpPColor parameter.
 
Every graphics device driver must export a ColorInfo function.
 
Parameter  Description
────────────────────────────────────────────────────────────────────────────
 
lpDestDev  Points to a PDEVICE or PBITMAP structure specifying the
           destination device or bitmap.
 
dwColorin  Specifies either a logical or physical color, depending on the
           value of lpPColor parameter.
 
lpPColor   Points to a PCOLOR structure or is NULL. If lpPColor points to a
           PCOLOR structure, the function assumes that dwColorin specifies a
           logical color (an RGB value) and copies the physical color value
           that most closely matches the logical color to this structure. If
           lpPColor is NULL, the function assumes that dwColorin specifies a
           physical color and returns the logical color that matches the
           physical color.
 
Return Value
 
The return value is the logical color (RGB value) that most closely matches
the physical color either specified by dwColorin, or copied to the PCOLOR
structure pointed to by lpPColor.
 
Comments
 
The export ordinal for this function is 2.
 
When converting a logical color, ColorInfo chooses the best possible
physical color to match the logical color and return the RGB color value
that corresponds to this physical color.
 
GDI uses the physical colors returned by ColorInfo to set text colors,
background colors, and pixel colors using the Pixel function.
 
If dwColorin is a logical color, it may specify either an RGB value or a
color index. If dwColorin specifies a color index (high-order byte is 0xFF),
ColorInfo should return the index without carrying out a conversion. If
dwColorin is a physical color, ColorInfo should return an RGB value only for
static colors and return color indexes for all other colors. If GDI receives
a color index from ColorInfo, it uses other functions to determine the
corresponding logical color.
 
See Also
 
Pixel