Documentation
[SDK Documentation] [CGapiCursor]
CGapiGradient
Overview
CGapiGradient is used to pre-render a gradient that can later be drawn using CGapiSurface::DrawGradient.
This document has been updated for use with GapiDraw 4.0 or later.
Last updated on October 5, 2008.
CGapiCursor::CreateGradient
This method creates the gradient.
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HRESULT CreateGradient(DWORD dwNumPixels, COLORREF cFirst, COLORREF cLast); |
Parameters
- dwNumPixels
- Number of pixel steps of the gradient. Must match the width and height of the clipped rectangle that is later used to draw the gradient.
- cFirst
- The first color.
- cLast
- The last color.
Return values
If this method succeeds, the return value is GD_OK.
If the method fails, the return value may be one of the following return values:
GDERR_INVALIDPARAMS
Remarks
GapiGradient uses six multiplications and six divisions for each pixel in the gradient (since it is precalculated in two directions), so it is not recommended to re-create the entire gradient on each frame update. You might instead want to create several gradients as member variables for re-use.
CGapiCursor::GetNumPixels
Returns the number of pixels in the gradient.
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DWORD GetNumPixels(); |
Parameters
None
Return values
Returns the number of pixels in the gradient.
CGapiCursor::GetFirstColor
Returns the first color of the gradient.
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HRESULT GetFirstColor(COLORREF* pFirst); |
- pFirst
- Will be set to the first color of the gradient.
Return values
If this method succeeds, the return value is GD_OK.
If the method fails, the return value may be one of the following return values:
GDERR_INVALIDPARAMS
GDERR_NOTINITIALIZED
CGapiCursor::GetLastColor
Returns the last color of the gradient.
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HRESULT GetLastColor(COLORREF* pLast); |
- pLast
- Will be set to the last color of the gradient.
Return values
If this method succeeds, the return value is GD_OK.
If the method fails, the return value may be one of the following return values:
GDERR_INVALIDPARAMS
GDERR_NOTINITIALIZED
