pjs/gfx/public/nsIImage.h

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#ifndef nsIImage_h___
#define nsIImage_h___

#include "nsISupports.h"
#include "nsIRenderingContext.h"

struct nsRect;
class nsIDeviceContext;

struct nsColorMap
{
  //I lifted this from the image lib. The difference is that
  //this uses nscolor instead of NI_RGB. Multiple color pollution
  //is a bad thing. MMP
  PRInt32 NumColors;  // Number of colors in the colormap.
                      // A negative value can be used to denote a
                      // possibly non-unique set.
  //nscolor *Map;       // Colormap colors.
  PRUint8 *Index;     // NULL, if map is in index order, otherwise
                      // specifies the indices of the map entries. */
};

typedef enum {
    nsMaskRequirements_kNoMask,
    nsMaskRequirements_kNeeds1Bit,
    nsMaskRequirements_kNeeds8Bit
} nsMaskRequirements;


#define  nsImageUpdateFlags_kColorMapChanged 0x1
#define  nsImageUpdateFlags_kBitsChanged     0x2
 
// IID for the nsIImage interface
#define NS_IIMAGE_IID          \
{ 0x0b4faaa0, 0xaa3a, 0x11d1, \
{ 0xa8, 0x24, 0x00, 0x40, 0x95, 0x9a, 0x28, 0xc9 } }

// Interface to Images
class nsIImage : public nsISupports
{

public:
  NS_DEFINE_STATIC_IID_ACCESSOR(NS_IIMAGE_IID)

  /**
   * Build and initialize the nsIImage
   * @param aWidth The width in pixels of the desired pixelmap
   * @param aHeight The height in pixels of the desired pixelmap
   * @param aDepth The number of bits per pixel for the pixelmap
   * @param aMaskRequirements A flag indicating if a alpha mask should be allocated 
   */
  virtual nsresult Init(PRInt32 aWidth, PRInt32 aHeight, PRInt32 aDepth, nsMaskRequirements aMaskRequirements) = 0;

  /**
   * Get the number of bytes per pixel for this image
   * @update - dwc 2/3/99
   * @return - the number of bytes per pixel
   */
  virtual PRInt32 GetBytesPix() = 0;

  /**
   * Get whether rows are organized top to bottom, or bottom to top 
   * @update - syd 3/29/99 
   * @return PR_TRUE if top to bottom, else PR_FALSE 
   */
  virtual PRBool GetIsRowOrderTopToBottom() = 0;

  /**
   * Get the width for the pixelmap
   * @update - dwc 2/1/99
   * @return The width in pixels for the pixelmap
   */
  virtual PRInt32 GetWidth() = 0;

  /**
   * Get the height for the pixelmap
   * @update - dwc 2/1/99
   * @return The height in pixels for the pixelmap
   */
  virtual PRInt32 GetHeight() = 0;

  /**
   * Get a pointer to the bits for the pixelmap, only if it is not optimized
   * @update - dwc 2/1/99
   * @return address of the DIB pixel array
   */
  virtual PRUint8 * GetBits() = 0;

  /**
   * Get the number of bytes needed to get to the next scanline for the pixelmap
   * @update - dwc 2/1/99
   * @return The number of bytes in each scanline
   */
  virtual PRInt32 GetLineStride() = 0;

  /**
   * Get whether this image has an alpha mask. Preferable to testing
   * if GetAlphaBits() is non-null.
   * @update - sfraser 10/19/99
   * @return PR_TRUE if the image has an alpha mask, PR_FALSE otherwise
   */
  virtual PRBool GetHasAlphaMask() = 0;

  /**
   * Get a pointer to the bits for the alpha mask
   * @update - dwc 2/1/99
   * @return address of the alpha mask pixel array
   */
  virtual PRUint8 * GetAlphaBits() = 0;

  /**
   * Get the number of bytes per scanline for the alpha mask
   * @update - dwc 2/1/99
   * @return The number of bytes in each scanline
   */
  virtual PRInt32 GetAlphaLineStride() = 0;

  /**
   * Update the nsIImage color table
   * @update - dwc 2/1/99
   * @param aFlags Used to pass in parameters for the update
   * @param aUpdateRect The rectangle to update
   */
  virtual void ImageUpdated(nsIDeviceContext *aContext, PRUint8 aFlags, nsRect *aUpdateRect) = 0;

  /**
   * Converted this pixelmap to an optimized pixelmap for the device
   * @update - dwc 2/1/99
   * @param aContext The device to optimize for
   * @return the result of the operation, if NS_OK, then the pixelmap is optimized
   */
  virtual nsresult Optimize(nsIDeviceContext* aContext) = 0;

  /**
   * Get the colormap for the nsIImage
   * @update - dwc 2/1/99
   * @return if non null, the colormap for the pixelmap,otherwise the image is not color mapped
   */
  virtual nsColorMap * GetColorMap() = 0;

  /**
   * BitBlit the nsIImage to a device, the source can be scaled to the dest
   * @update - dwc 2/1/99
   * @param aSurface  the surface to blit to
   * @param aX The destination horizontal location
   * @param aY The destination vertical location
   * @param aWidth The destination width of the pixelmap
   * @param aHeight The destination height of the pixelmap
   * @return if TRUE, no errors
   */
  NS_IMETHOD Draw(nsIRenderingContext &aContext, nsIDrawingSurface* aSurface, PRInt32 aX, PRInt32 aY, PRInt32 aWidth, PRInt32 aHeight) = 0;

  /**
   * BitBlit the nsIImage to a device, the source and dest can be scaled
   * @update - dwc 2/1/99
   * @param aSurface  the surface to blit to
   * @param aSX The source width of the pixelmap
   * @param aSY The source vertical location
   * @param aSWidth The source width of the pixelmap
   * @param aSHeight The source height of the pixelmap
   * @param aDX The destination horizontal location
   * @param aDY The destination vertical location
   * @param aDWidth The destination width of the pixelmap
   * @param aDHeight The destination height of the pixelmap
   * @return if TRUE, no errors
   */
  NS_IMETHOD Draw(nsIRenderingContext &aContext, nsIDrawingSurface* aSurface, PRInt32 aSX, PRInt32 aSY, PRInt32 aSWidth, PRInt32 aSHeight,
                  PRInt32 aDX, PRInt32 aDY, PRInt32 aDWidth, PRInt32 aDHeight) = 0;


  NS_IMETHOD DrawTile(nsIRenderingContext &aContext,
                      nsIDrawingSurface* aSurface,
                      PRInt32 aSXOffset, PRInt32 aSYOffset,
                      PRInt32 aPadX, PRInt32 aPadY,
                      const nsRect &aTileRect) = 0;

  /**
   * BitBlit the entire (no cropping) nsIImage to another nsImage, the source and dest can be scaled
   * @update - saari 03/08/01
   * @param aDstImage  the nsImage to blit to
   * @param aDX The destination horizontal location
   * @param aDY The destination vertical location
   * @param aDWidth The destination width of the pixelmap
   * @param aDHeight The destination height of the pixelmap
   * @return if TRUE, no errors
   */
  NS_IMETHOD DrawToImage(nsIImage* aDstImage, PRInt32 aDX, PRInt32 aDY, PRInt32 aDWidth, PRInt32 aDHeight) = 0;

  /**
   * Get the alpha depth for the image mask
   * @update - lordpixel 2001/05/16
   * @return  the alpha mask depth for the image, ie, 0, 1 or 8
   */
  virtual PRInt8 GetAlphaDepth() = 0;

  /**
   * Return information about the bits for this structure
   * @update - dwc 2/1/99
   * @return a bitmap info structure for the Device Dependent Bits
   */
  virtual void* GetBitInfo() = 0;


  /**
   * LockImagePixels
   * Lock the image pixels so that we can access them directly,
   * with safely. May be a noop on some platforms.
   *
   * aMaskPixels = PR_TRUE for the mask, PR_FALSE for the image
   *
   * Must be balanced by a call to UnlockImagePixels().
   *
   * @update - sfraser 10/18/99
   * @return error result
   */
  NS_IMETHOD LockImagePixels(PRBool aMaskPixels) = 0;
  
  /**
   * UnlockImagePixels
   * Unlock the image pixels. May be a noop on some platforms.
   *
   * Should balance an earlier call to LockImagePixels().
   *
   * aMaskPixels = PR_TRUE for the mask, PR_FALSE for the image
   *
   * @update - sfraser 10/18/99
   * @return error result
   */
  NS_IMETHOD UnlockImagePixels(PRBool aMaskPixels) = 0;
};

#endif