| class CBitmapContext : public CGraphicsContext |
An abstract, device-independent, interface to bitmapped graphics contexts.
This holds the setting used to draw to a CBitmapDevice.
The default settings of a CBitmapContext object immediately after construction are:
drawing mode is EDrawModePen (pen and brush colours used as they are)
no clipping rectangle
pen settings are: black, solid, single pixel width
brush style is null
no text font selected
The classes CFbsBitGc and CWindowGc are derived from this class.
| Public Member Functions | |
|---|---|
| TInt | AlphaBlendBitmaps(const TPoint &, const CFbsBitmap *, const TRect &, const CFbsBitmap *, const TPoint &) |
| TInt | AlphaBlendBitmaps(const TPoint &, const CWsBitmap *, const TRect &, const CWsBitmap *, const TPoint &) |
| void | BitBlt(const TPoint &, const CFbsBitmap *) |
| void | BitBlt(const TPoint &, const CFbsBitmap *, const TRect &) |
| void | BitBltMasked(const TPoint &, const CFbsBitmap *, const TRect &, const CFbsBitmap *, TBool) |
| void | Clear() |
| void | Clear(const TRect &) |
| void | CopyRect(const TPoint &, const TRect &) |
| void | SetFaded(TBool) |
| void | SetFadingParameters(TUint8, TUint8) |
| Protected Member Functions | |
|---|---|
| IMPORT_C TInt | APIExtension(TUid, TAny *&, TAny *) |
| IMPORT_C void | Reserved_CBitmapContext_1() |
| IMPORT_C void | Reserved_CBitmapContext_2() |
| IMPORT_C void | Reserved_CBitmapContext_3() |
| IMPORT_C void | Reserved_CGraphicsContext_2() |
| Inherited Enumerations | |
|---|---|
| CGraphicsContext:TBrushStyle | |
| CGraphicsContext:TDrawMode | |
| CGraphicsContext:TDrawModeComponents | |
| CGraphicsContext:TFillRule | |
| CGraphicsContext:TPenStyle | |
| CGraphicsContext:TTextAlign | |
| IMPORT_C TInt | APIExtension | ( | TUid | aUid, |
| TAny *& | aOutput, | |||
| TAny * | aInput | |||
| ) | [protected, virtual] | |||
An APIExtension method to allow the addition of new APIs to retain compatibility with previous versions of gdi.dll CGraphicsContext WARNING: Function for internal use ONLY. Compatibility is not guaranteed in future releases.
| TInt | AlphaBlendBitmaps | ( | const TPoint & | aDestPt, |
| const CFbsBitmap * | aSrcBmp, | |||
| const TRect & | aSrcRect, | |||
| const CFbsBitmap * | aAlphaBmp, | |||
| const TPoint & | aAlphaPt | |||
| ) | [pure virtual] | |||
S - a pixel from aSrcBmp;
W - a pixel from the window;
A - a pixel from aAlphaBmp; The contents of source and alpha bitmap are preserved. The calculated alpha blended pixels are written to the destination CBitmapContext.
| const TPoint & aDestPt | Position in the target the result should be drawn to. |
| const CFbsBitmap * aSrcBmp | A pointer to the source bitmap. |
| const TRect & aSrcRect | The part of the source bitmap that should be used. |
| const CFbsBitmap * aAlphaBmp | A pointer to the bitmap used as an alpha blending factor. |
| const TPoint & aAlphaPt | Position of the first pixel in the alpha bitmap that should be used as a source for the alpha blending. The size of the area is the same as the source bitmap area - aSrcRect parameter. |
| TInt | AlphaBlendBitmaps | ( | const TPoint & | aDestPt, |
| const CWsBitmap * | aSrcBmp, | |||
| const TRect & | aSrcRect, | |||
| const CWsBitmap * | aAlphaBmp, | |||
| const TPoint & | aAlphaPt | |||
| ) | [pure virtual] | |||
The method performs an alpha blending of the source data, aSrcBmp, with the CBitmapContext, using the data from aAlphaBmp as an alpha blending factor. For information on how this function works, see the other overload.
| const TPoint & aDestPt | Position in the target the result should be drawn to. |
| const CWsBitmap * aSrcBmp | A pointer to the source bitmap. |
| const TRect & aSrcRect | The part of the source bitmap that should be used. |
| const CWsBitmap * aAlphaBmp | A pointer to the bitmap used as an alpha blending factor. |
| const TPoint & aAlphaPt | Position of the first pixel in the alpha bitmap that should be used as a source for the alpha blending. The size of the area is the same as the source bitmap area - aSrcRect parameter. |
| void | BitBlt | ( | const TPoint & | aPoint, |
| const CFbsBitmap * | aBitmap | |||
| ) | [pure virtual] | |||
Performs a bitmap block transfer.
This pure virtual function is implemented in derived classes.
| const TPoint & aPoint | The destination for the top left corner of the transferred bitmap. It is relative to the top left corner of the destination bitmap, which may be the screen. |
| const CFbsBitmap * aBitmap | A memory-resident bitmap. |
| void | BitBlt | ( | const TPoint & | aPoint, |
| const CFbsBitmap * | aBitmap, | |||
| const TRect & | aRect | |||
| ) | [pure virtual] | |||
Performs a bitmap block transfer of a rectangular piece of a bitmap.
If the specified rectangle is larger than the bitmap then the bitmap is padded with white.
This pure virtual function is implemented in derived classes.
| const TPoint & aPoint | The destination for the top left corner of the transferred bitmap. It is relative to the top left corner of the destination bitmap, which may be the screen. |
| const CFbsBitmap * aBitmap | A memory-resident bitmap |
| const TRect & aRect | A rectangle defining the portion of the bitmap to transfer. Its coordinates are relative to the top left corner of the source bitmap. |
| void | BitBltMasked | ( | const TPoint & | aPoint, |
| const CFbsBitmap * | aBitmap, | |||
| const TRect & | aSourceRect, | |||
| const CFbsBitmap * | aMaskBitmap, | |||
| TBool | aInvertMask | |||
| ) | [pure virtual] | |||
Performs a masked bitmap block transfer.
The mask bitmap can be used as either a positive or negative mask. Masked pixels are not mapped to the destination rectangle.
This function uses either a black and white (binary) mask bitmap, or if aMaskBitmap's display mode is EGray256, alpha blending is used. Use of any other mode may result in unpredictable results
With aInvertMask=EFalse, black pixels in the mask bitmap stop corresponding pixels in the source bitmap from being transferred to the destination rectangle. With aInvertMask=ETrue, white pixels in the mask bitmap stop corresponding pixels in the source bitmap from being transferred to the destination rectangle.
Note that if the mask bitmap is smaller than the source bitmap, then it is tiled across the bitmap. Note that the mask is applied before the piece of the bitmap is defined - the mask is tiled relative to the top left of the original source bitmap rather than the top left of the bitmap piece.
This pure virtual function is implemented in derived classes.
| const TPoint & aPoint | The destination for the top left corner of the transferred bitmap. It is relative to the top left corner of the destination bitmap, which may be the screen. |
| const CFbsBitmap * aBitmap | A memory-resident source bitmap. |
| const TRect & aSourceRect | A rectangle defining the piece of the bitmap to be drawn, with co-ordinates relative to the top left corner of the bitmap. |
| const CFbsBitmap * aMaskBitmap | A mask bitmap |
| TBool aInvertMask | If EFalse, a source pixel that is masked by a black pixel is not transferred to the destination rectangle. If ETrue, then a source pixel that is masked by a white pixel is not transferred to the destination rectangle. |
| void | Clear | ( | ) | [pure virtual] |
Clears the whole bitmap.
The cleared area is filled with the current brush colour.
This pure virtual function is implemented in derived classes.
| void | Clear | ( | const TRect & | aRect | ) | [pure virtual] |
Clears a rectangular area of a bitmap.
The cleared area is filled with the current brush colour.
This pure virtual function is implemented in derived classes.
| const TRect & aRect | The rectangle to clear. |
| void | CopyRect | ( | const TPoint & | aOffset, |
| const TRect & | aRect | |||
| ) | [pure virtual] | |||
Copies a rectangle.
This pure virtual function is implemented in derived classes.
| IMPORT_C void | Reserved_CGraphicsContext_2 | ( | ) | [protected, virtual] |
A reserved virtual function for future use.
| void | SetFaded | ( | TBool | aFaded | ) | [pure virtual] |
Sets whether the graphics context is faded.
| TBool aFaded | ETrue to fade the GC; EFalse to unfade it. |
| void | SetFadingParameters | ( | TUint8 | aBlackMap, |
| TUint8 | aWhiteMap | |||
| ) | [pure virtual] | |||
Sets the fading parameters.
This function allows you to override the map used when drawing with a faded graphics context (GC). However if you draw to a faded window with a faded GC, then fading on the GC is ignored and the fading of the window is used.
Fading is used to change the colour of a window to make other windows stand out. Fading can either make a faded window closer to white or closer to black.
Fading re-maps colours in the faded GC to fall between the specified black and white map values. If aBlackMap=0 and aWhiteMap=255 then the colours are mapped unchanged. As the values converge the colours are mapped to a smaller range - so the differences between colours in the faded GC decrease. If the values are reversed then the colours are inverted (i.e. where the GC would be black, it is now white).