LEADTOOLS GDI/GDI+ (Leadtools.Drawing assembly)

RasterPaintDibInfo Class

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Example 





Members 
This class describes the image data expected by the custom paint callbacks. It is used with the RasterPaintCallbacks callbacks.
Object Model
Syntax
public class RasterPaintDibInfo 
'Declaration
 
Public Class RasterPaintDibInfo 
'Usage
 
Dim instance As RasterPaintDibInfo

            

            
public ref class RasterPaintDibInfo 
Remarks

The user will typically allocate this class and return it from the RasterImagePaintCallbackFunction.GetDibInfoCallback callback.

Example

This example will show how to indicate that the graphics device expects a 16-bit image with the image data in the low 12 bits. Also, this particular card expected the data to be top-down, unlike the usual GDI functions which expect the data to be upside-down.

The example is in C++/CLI because this is the most useful language for implementing these classes.

Copy Code  
// macro that calculates the number of bytes per line, rounding up to a multiple of 4 bytes
#define DIB_WIDTH_BYTES(pixels) ((((pixels) + 31) & ~31) >> 3)
             
Object^ myPaintCallbacks::GetDibInfoCallback(RasterImage^ image, array<Object^>^ args)
{
   // make sure the parameters are correct
   if(args->Length != 2 || image == nullptr)
   {
      throw gcnew RasterException(RasterExceptionCode::InvalidParameter);
      return nullptr;
   }
   UInt32 uWidth = (UInt32)args[1];
   RasterPaintDibInfo^ pDibInfo = gcnew RasterPaintDibInfo;
   if(pDibInfo == nullptr)
   {
      throw gcnew RasterException(RasterExceptionCode::NoMemory);
      return nullptr;
   }
            
   pDibInfo->Default();
   pDibInfo->BitsPerPixel = 16;          // paint using 16-bit data, although there are only 12 significant bits
   pDibInfo->PlaneCount = 1;             // One plane
   pDibInfo->BytesPerLine = DIB_WIDTH_BYTES(uWidth * 16);   // bytes per line is a multiple of 4 bytes
   pDibInfo->ViewPerspective = RasterViewPerspective::TopLeft; // the data should be TOP_LEFT, not BOTTOM_LEFT like the data in the regular GDI functions
   pDibInfo->Order = RasterByteOrder::Gray;         // gray bitmap
            
   // indicate that the data should be in the low 12 bits
   pDibInfo->Flags = RasterPaintDibInfoFlags::LowHighBitValid;
   pDibInfo->LowBit = 0;
   pDibInfo->HighBit = 11;
            
   return pDibInfo;
}
Requirements

Target Platforms

See Also

Reference

RasterPaintDibInfo Members
Leadtools.Drawing Namespace
RasterPaintCallbacks Class
RasterPaintProperties.PaintCallbacks
Implementing custom paint

 

 


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