Sets the color to be used as a transparent color.


#include "l_bitmap.h"

L_LTANN_API L_INT L_AnnSetTransparentColor(hObject, crTransparent, uFlags)



Handle to the annotation object.

COLORREF crTransparent

The fill color. The standard Windows values for COLORREF represent either red, green, and blue color values, or an index into the bitmap's palette. A COLORREF value with the format 0x00BBGGRR represents the blue, green, and red color values for the specified pixel, where 0xBB is the blue value, 0xGG is the green value and 0xRR is the red value. If 0x01000000 is set in the COLORREF value (0x010000ZZ), the lower 8 bits (0xZZ) represent an index into the bitmap's palette which holds the color value. These COLORREF values can be used with any Windows function and macro that takes a COLORREF parameter.

In the Document and Medical Imaging toolkits the COLORREF value may represent a 16 bit grayscale value if pBitmap is a 12 or 16-bit grayscale bitmap. So that the value is not confused with an RGB value, the COLORREF_GRAY16 mask (0x04000000) is set. In this case (0x0400YYYY), the lower 16 bits (0xYYYY) of the COLORREF value represent the 16-bit grayscale value. (0x0400FFFF is 16-bit white and 0x04000000is 16-bit black.) This is not a standard Windows value. Therefore, LEADTOOLS functions will recognize a COLORREF having this format, but Windows functions will not. For information on how to use a 16-bit grayscale COLORREF in a non-LEADTOOLS function, refer to L_GetPixelColor.

L_UINT uFlags

Flags that determine which objects to process. Most of the flags apply only to container objects. You can combine values when appropriate by using a bitwise OR ( | ). The following are valid values:

Value Meaning
0 Process only the specified object.
ANNFLAG_SELECTED [0x0001] Process only objects that have the selected property set to TRUE. For getting and setting the selected property, use the L_AnnGetSelected and L_AnnSetSelected functions.
ANNFLAG_NOTTHIS [0x0004] Process only one level of objects within the specified container, not the container itself. If there are containers within the container, they are modified, but the objects within them are not.
ANNFLAG_RECURSE [0x0008] Process objects within a container, and within any subcontainers, down to any level.
ANNFLAG_NOTCONTAINER [0x0002] (Used with ANNFLAG_RECURSE) Process objects within containers, not the containers themselves.
ANNFLAG_NOINVALIDATE [0x0010] Do not invalidate the affected rectangle in the window. Use this to avoid generating unwanted paint messages.
ANNFLAG_CHECKMENU [0x0020] Process objects only if the ANNAUTOTEXT_MENU_TRANSPARENTCOLOR menu item has been selected.


Value Meaning
SUCCESS The function was successful.
< 1 An error occurred. Refer to Return Codes.


The L_AnnSetTransparentColor function is valid only for the following object types when they are using a bitmap:

In addition, the Automation object stores transparency settings along with the other object default settings.

A transparent color is not painted when the image is painted. This transparent color is used only if the object is set to transparent using L_AnnSetTransparent.

By default, the transparent color is white (0x00FFFFFF).

If hObject is a container object, then uFlags indicates which objects to process. If hObject is an automation object, all objects created by this automation object will have this transparent color.

In design mode, the transparent color can be picked by selecting the Transparent color from the properties menu. If the objects bitmap has a palette, a dialog box will appear so that a color can be selected from the palette colors. If the objects bitmap does not have a palette, the standard Windows color pick dialog box is used to select a transparent color.

Call the L_AnnGetTransparent function to get a value that indicates whether the bitmap being used by the annotation object is using a transparent color. Call the L_AnnGetTransparentColor function to get a value that indicates which color is being used as the transparent color.

Required DLLs and Libraries


Win32, x64.

See Also




L_INT EXT_CALLBACK annEnumCallback(HANNOBJECT hObject, L_VOID* pUserData) 
   L_UINT      Type; 
   L_COLORREF  TransColor; 
   L_INT       nRet; 
   nRet = L_AnnGetType(hObject, &Type); 
   if (nRet != SUCCESS) 
      return nRet; 
   if (Type != ANNOBJECT_STAMP) 
      _tprintf(_T("%s"), TEXT("Notice: Object must be a stamp.")); 
      return FAILURE; 
   nRet = L_AnnGetTransparentColor(hObject, &TransColor); 
   if (nRet != SUCCESS) 
      _tprintf(_T("%s"), TEXT("Error getting transparent color.")); 
      return nRet; 
   if (TransColor != RGB(0, 0, 0)) 
      _tprintf(_T("%s"), TEXT("Transparent color set.")); 
      nRet = L_AnnSetTransparent(hObject, L_TRUE, 0); 
      if (nRet != SUCCESS) 
         return nRet; 
      TransColor = RGB(0, 0, 0); 
      nRet = L_AnnSetTransparentColor(hObject, TransColor, 0); 
      if (nRet != SUCCESS) 
         return nRet; 
   return SUCCESS; 
extern "C" L_INT AnnSetTransparentColorExample(HANNOBJECT hContainer) 
   return L_AnnEnumerate(hContainer, (ANNENUMCALLBACK)annEnumCallback, NULL, ANNFLAG_RECURSE | ANNFLAG_SELECTED, NULL); 
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LEADTOOLS Raster Imaging C API Help

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© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.