PRB: Area Around Text and Remainder of Window Different Colors

• Microsoft Windows Software Development Kit (SDK) for Windows versions 3.1 and 3.0
• Microsoft Win32 Application Programming Interface (API) included with:

      - Microsoft Windows NT versions 3.5 and 3.51
      - Microsoft Windows 95 version 4.0
  

SYMPTOMS

When text is painted into a window, an area around the text is a different color than the remainder of the window.

CAUSE

The area around the text is painted with a solid color while the remainder of the window is painted using a dithered color.

RESOLUTION

To make the area around the text and the remainder of the window have the same color, perform one of the following two steps:

• Use a solid color for the window background, and use the same color for the text background. To ensure that a color is a solid color, use the GetNearestColor function. This function returns the nearest solid color available to represent the specified color.

  -or-

• Call the SetBkMode function to specify TRANSPARENT mode for the text. Doing so prevents Windows from painting the area behind the text. The window background color shows through instead.

MORE INFORMATION

By default, when an application paints text into its window, Windows fills the area around the character with the current background color. Windows always uses a solid color for this purpose.

When an application registers a window class, it specifies a handle to a brush that Windows uses to paint the window background. On some output devices, brushes can create dithered colors. On one of these devices, the area behind painted text might have a different color than the remainder of the window.

The following code specifies the window background color:

   #define ELANGREEN  0x003FFF00
   pTemplateClass->hbrBackground = CreateSolidBrush((DWORD)ELANGREEN);

   #define SZ -1
   SetBkColor(hDC, (DWORD)ELANGREEN);
   DrawText(hDC, (LPSTR)"text", SZ, (LPRECT)&Rect, DT_BOTTOM);

A brush may be able to represent a wider color range than the solid colors because a brush covers an area while a solid color may be used to paint nominal-width lines (for example, lines that are one device unit wide) that must be the same color at all locations and angles. Therefore, the device-driver writer has the option of providing dithered colors for brushes, but has no such freedom when it comes to the solid colors for drawing lines.