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L_EfxGradientFillRect

Summary

Draws a rectangle into the target device context, and then fills the rectangle with a gradient from the specified starting color to the specified ending color.

Syntax

#include "l_bitmap.h"

L_LTEFX_API L_INT L_EfxGradientFillRect(hDC, pRect, uStyle, crStart, crEnd, uSteps)

Parameters

HDC hDC

Handle to the target device context.

RECT * pRect

Pointer to the display destination rectangle.

L_UINT uStyle

Gradient style. For valid values, refer to Effect Gradient Styles.

COLORREF crStart

COLORREF value that specifies the starting color.

COLORREF crEnd

COLORREF value that specifies the ending color.

L_UINT uSteps

Number of gradient color steps. Valid values are 2 to 256.

Returns

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

Required DLLs and Libraries

LTEFX
For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.

Platforms

Win32, x64.

Example

This example shows the minimum requirements for using the L_EfxGradientFillRect function to draw and fill a rectangle with a color gradient.

L_INT EfxGradientFillRectExample(HWND hWnd, RECT* pDest) 
{ 
   L_INT     nRet; 
   HDC       hdc;                   // Device context for the current window 
   HPALETTE  hSavedPalette = NULL;  // Temporary copy of the current system palette 
   HPALETTE  hOurPalette = NULL;    // The palette that we will use to paint 
   L_INT     nBitsPerPixel; 
 
   // Get the device context 
   hdc = GetDC(hWnd); 
 
   // Check the device to see if we need a palette 
   nBitsPerPixel = GetDeviceCaps(hdc, BITSPIXEL) * GetDeviceCaps(hdc, PLANES); 
   if (nBitsPerPixel <= 8) 
   { 
      hOurPalette = (HPALETTE)GetStockObject(DEFAULT_PALETTE); 
      hSavedPalette = SelectPalette(hdc, hOurPalette, FALSE); 
 
      // Realize our palette 
      RealizePalette(hdc); 
   } 
 
   // Draw the gradient filled rectangle 
   nRet = L_EfxGradientFillRect(hdc,   // device context 
      pDest,                           // destination rectangle 
      EFX_GRADIENT_ELLIPSE_TO_C,       // out to center 
      RGB(255, 0, 0),                  // starting color, red 
      RGB(0, 0, 255),                  // ending color, blue 
      12);                             // gradient color steps 
   if (nRet != SUCCESS) 
      return nRet; 
 
   // Restore the old palette 
   if (hOurPalette) 
      SelectPalette(hdc, hSavedPalette, FALSE); 
 
   // Release the device context 
   ReleaseDC(hWnd, hdc); 
 
   return SUCCESS; 
}