PRB: Errors When Edit Bitmaps with More than 16 or 256 Colors

WINDOWS        | WINDOWS NT

The information in this article applies to:

• The Resource Editor included with:

  - Microsoft Visual C++ for Windows, versions 1.5, 1.51, 1.52 - Microsoft Visual C++, 32-bit Edition, versions 2.0, 2.1 and 4.0

SYMPTOMS

The 16-bit Resource Editor (AppStudio) generates the following message while attempting to edit a bitmap that contains more than 16 colors:

    "Cannot open bitmap for editing.
      Unsupported color resolution."

    "Only 2-, 16-, and 256-color bitmaps are supported."

CAUSE

The Resource Editor for the 16-bit versions cannot display or edit bitmaps that contain more than 16 colors, and the Resource Editor for the 32-bit versions cannot display or edit bitmaps that contain more than 256 colors.

RESOLUTION

Choose another graphics editor such as PBRUSH.EXE (Paintbrush) in the Accessories group on Windows and Windows NT or MSPAINT.EXE (Paint) from the Accessories folder on Windows 95 to create or edit the offending bitmaps. Then import them into the resource script.

NOTE: Once you import the picture into the resource file, you will not be able to edit it or display it.

STATUS

This behavior is by design.

MORE INFORMATION

The 16-bit AppStudio cannot display bitmaps that have more than 16 colors. Sometimes, as a result of this, you will notice that when the file is open for display, AppStudio might automatically change the colors to their closest 16-color approximations without warning you. This limitation depends on which version of Microsoft Visual C++ you use. For example, versions 1.5 and above prompt you, while version 1.0 provides no warning. If the change takes effect, the bitmap is changed to 16 colors; it cannot be changed back to 256 colors.

Microsoft Visual C++, 32-bit Edition, allows you to edit bitmaps that contain up to 256 colors. If your video resolution supports more than 256 colors, you will see one of these error messages:

   <bitmap file path> Cannot load file. The current display device does not
   support palettes which are required for editing 256-color bitmaps.

   -or-

   <bitmap file path> Cannot load file. The Video driver does not support
   enough colors to load this image.