gecko-dev/gfx/public/nsIDeviceContext.h

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * The contents of this file are subject to the Netscape Public License
 * Version 1.0 (the "NPL"); you may not use this file except in
 * compliance with the NPL.  You may obtain a copy of the NPL at
 * http://www.mozilla.org/NPL/
 *
 * Software distributed under the NPL is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
 * for the specific language governing rights and limitations under the
 * NPL.
 *
 * The Initial Developer of this code under the NPL is Netscape
 * Communications Corporation.  Portions created by Netscape are
 * Copyright (C) 1998 Netscape Communications Corporation.  All Rights
 * Reserved.
 */

#ifndef nsIDeviceContext_h___
#define nsIDeviceContext_h___

#include "nsISupports.h"
#include "nsCoord.h"
#include "nsRect.h"
#include "nsIWidget.h"

class nsIRenderingContext;
class nsIView;
class nsIFontMetrics;
class nsIWidget;
class nsIDeviceContextSpec;

struct nsFont;
struct nsColor;

//a cross platform way of specifying a native device context
typedef void * nsNativeDeviceContext;

#define NS_IDEVICE_CONTEXT_IID   \
{ 0x5931c580, 0xb917, 0x11d1,    \
{ 0xa8, 0x24, 0x00, 0x40, 0x95, 0x9a, 0x28, 0xc9 } }

//a cross platform way of specifying a native palette handle
typedef void * nsPalette;

//structure used to return information about a device's palette capabilities
struct nsPaletteInfo {
  PRPackedBool  isPaletteDevice;
  PRUint8       sizePalette;  // number of entries in the palette
  PRUint8       numReserved;  // number of reserved palette entries
  nsPalette     palette;      // native palette handle
};

/**
 *
 *
 */
  typedef enum {
    // Colors
    eSystemAttr_Color_WindowBackground,
    eSystemAttr_Color_WindowForeground,
    eSystemAttr_Color_WidgetBackground,
    eSystemAttr_Color_WidgetForeground,
    eSystemAttr_Color_WidgetSelectBackground,
    eSystemAttr_Color_WidgetSelectForeground,
    eSystemAttr_Color_Widget3DHighlight,
    eSystemAttr_Color_Widget3DShadow,
    eSystemAttr_Color_TextBackground,
    eSystemAttr_Color_TextForeground,
    eSystemAttr_Color_TextSelectBackground,
    eSystemAttr_Color_TextSelectForeground,
    // Size
    eSystemAttr_Size_WindowTitleHeight,
    eSystemAttr_Size_WindowBorderWidth,
    eSystemAttr_Size_WindowBorderHeight,
    eSystemAttr_Size_Widget3DBorder,
    eSystemAttr_Size_ScrollbarHeight,
    eSystemAttr_Size_ScrollbarWidth,
    // Fonts
    eSystemAttr_Font_Caption,
    eSystemAttr_Font_Icon,
    eSystemAttr_Font_Menu,
    eSystemAttr_Font_MessageBox,
    eSystemAttr_Font_SmallCaption,
    eSystemAttr_Font_StatusBar,
    eSystemAttr_Font_Tooltips,
    eSystemAttr_Font_Widget
  } nsSystemAttrID;

  typedef union {
    PRUint32   mSize;
    nscolor  * mColor;
    nsFont   * mFont;
  } SystemAttrStruct;

/**
 * Constants identifying pre-defined icons.
 * @see #LoadIcon()
 */
#define NS_ICON_LOADING_IMAGE 0
#define NS_ICON_BROKEN_IMAGE  1
#define NS_NUMBER_OF_ICONS    2

// XXX This is gross, but don't include libimg.h, because it includes ni_pixmap.h
// which includes xp_core.h which includes windows.h
struct _NI_ColorSpace;
typedef _NI_ColorSpace NI_ColorSpace;
typedef NI_ColorSpace IL_ColorSpace;

class nsIDeviceContext : public nsISupports
{
public:
  static const nsIID& IID() { static nsIID iid = NS_IDEVICE_CONTEXT_IID; return iid; }

  /**
   * Initialize the device context from a widget
   * @param aWidget a native widget to initialize the device context from
   * @return error status
   */
  NS_IMETHOD  Init(nsNativeWidget aWidget) = 0;

  /**
   * Create a rendering context and initialize it from an nsIView
   * @param aView view to initialize context from
   * @param aContext out parameter for new rendering context
   * @return error status
   */
  NS_IMETHOD  CreateRenderingContext(nsIView *aView, nsIRenderingContext *&aContext) = 0;

  /**
   * Create a rendering context and initialize it from an nsIWidget
   * @param aWidget widget to initialize context from
   * @param aContext out parameter for new rendering context
   * @return error status
   */
  NS_IMETHOD  CreateRenderingContext(nsIWidget *aWidget, nsIRenderingContext *&aContext) = 0;

  /**
   * Create a rendering context and initialize it. This API should *only* be called
   * on device contexts whose SupportsNativeWidgets() method return PR_FALSE.
   * @param aContext out parameter for new rendering context
   * @return error status
   */
  NS_IMETHOD  CreateRenderingContext(nsIRenderingContext *&aContext) = 0;

  /**
   * Initialize a rendering context from a widget. This method is only for use
   * when a rendering context was obtained directly from a factory rather than
   * through one of the Create* methods above.
   * @param aContext rendering context to initialize
   * @param aWindow widget to initialize context from
   * @return error status
   */
  NS_IMETHOD  InitRenderingContext(nsIRenderingContext *aContext, nsIWidget *aWindow) = 0;

  /**
   * Query the device to see if it supports native widgets. If not, then
   * nsIWidget->Create() calls should be avoided.
   * @param aSupportsWidgets out paramater. If PR_TRUE, then native widgets
   *        can be created.
   * @return error status
   */
  NS_IMETHOD  SupportsNativeWidgets(PRBool &aSupportsWidgets) = 0;

  /**
   * Obtain the size of a device unit relative to a Twip. A twip is 1/20 of
   * a point (which is 1/72 of an inch).
   * @param aDevUnitsToTwips out parameter for conversion value
   * @return error status
   */
  NS_IMETHOD  GetDevUnitsToTwips(float &aDevUnitsToTwips) const = 0;

  /**
   * Obtain the size of a Twip relative to a device unit.
   * @param aTwipsToDevUnits out parameter for conversion value
   * @return error status
   */
  NS_IMETHOD  GetTwipsToDevUnits(float &aTwipsToDevUnits) const = 0;

  /**
   * Set the scale factor to convert units used by the application
   * to device units. Typically, an application will query the device
   * for twips to device units scale and then set the scale
   * to convert from whatever unit the application wants to use
   * to device units. From that point on, all other parts of the
   * app can use the Get* methods below to figure out how
   * to convert device units <-> app units.
   * @param aAppUnits scale value to convert from application defined
   *        units to device units.
   * @return error status
   */
  NS_IMETHOD  SetAppUnitsToDevUnits(float aAppUnits) = 0;

  /**
   * Set the scale factor to convert device units to units
   * used by the application. This should generally be
   * 1.0f / the value passed into SetAppUnitsToDevUnits().
   * @param aDevUnits scale value to convert from device units to
   *        application defined units
   * @return error status
   */
  NS_IMETHOD  SetDevUnitsToAppUnits(float aDevUnits) = 0;

  /**
   * Get the scale factor to convert from application defined
   * units to device units.
   * @param aAppUnits out paramater for scale value
   * @return error status
   */
  NS_IMETHOD  GetAppUnitsToDevUnits(float &aAppUnits) const = 0;

  /**
   * Get the scale factor to convert from device units to
   * application defined units.
   * @param aDevUnits out paramater for scale value
   * @return error status
   */
  NS_IMETHOD  GetDevUnitsToAppUnits(float &aDevUnits) const = 0;

  /**
   * Get the value used to scale a "standard" pixel to a pixel
   * of the same physical size for this device. a standard pixel
   * is defined as a pixel on display 0. this is used to make
   * sure that entities defined in pixel dimensions maintain a
   * constant relative size when displayed from one output
   * device to another.
   * @param aScale out parameter for scale value
   * @return error status
   */
  NS_IMETHOD  GetCanonicalPixelScale(float &aScale) const = 0;

  /**
   * Get the width of a vertical scroll bar and the height
   * of a horizontal scrollbar in application units.
   * @param aWidth out parameter for width
   * @param aHeight out parameter for height
   * @return error status
   */
  NS_IMETHOD  GetScrollBarDimensions(float &aWidth, float &aHeight) const = 0;

  /**
   * Get the width of a vertical scroll bar and the height
   * of a horizontal scrollbar in application units.
   * @param anID The snum of the type of information you want back
   * @param aInfo out parameter for the system data
   * @return error status
   */
  NS_IMETHOD  GetSystemAttribute(nsSystemAttrID anID, SystemAttrStruct * aInfo) const = 0;

  /**
   * Get the nsIFontMetrics that describe the properties of
   * an nsFont.
   * @param aFont font description to obtain metrics for
   * @param aMetrics out parameter for font metrics
   * @return error status
   */
  NS_IMETHOD  GetMetricsFor(const nsFont& aFont, nsIFontMetrics*& aMetrics) = 0;

  //get and set the document zoom value used for display-time
  //scaling. default is 1.0 (no zoom)
  NS_IMETHOD  SetZoom(float aZoom) = 0;
  NS_IMETHOD  GetZoom(float &aZoom) const = 0;

  //get a low level drawing surface for rendering. the rendering context
  //that is passed in is used to create the drawing surface if there isn't
  //already one in the device context. the drawing surface is then cached
  //in the device context for re-use.
  NS_IMETHOD  GetDrawingSurface(nsIRenderingContext &aContext, nsDrawingSurface &aSurface) = 0;

  //functions for handling gamma correction of output device
  NS_IMETHOD  GetGamma(float &aGamms) = 0;
  NS_IMETHOD  SetGamma(float aGamma) = 0;

  //XXX the return from this really needs to be ref counted somehow. MMP
  NS_IMETHOD  GetGammaTable(PRUint8 *&aGammaTable) = 0;

  //load the specified icon. this is a blocking call that does not return
  //until the icon is loaded.
  //release the image when you're done
  NS_IMETHOD LoadIconImage(PRInt32 aId, nsIImage*& aImage) = 0;

  /**
   * Check to see if a particular named font exists.
   * @param aFontName character string of font face name
   * @return NS_OK if font is available, else font is unavailable
   */
  NS_IMETHOD CheckFontExistence(const nsString& aFaceName) = 0;
  NS_IMETHOD FirstExistingFont(const nsFont& aFont, nsString& aFaceName) = 0;

  NS_IMETHOD GetLocalFontName(const nsString& aFaceName, nsString& aLocalName,
                              PRBool& aAliased) = 0;

  /**
   * Attempt to free up resoruces by flushing out any fonts no longer
   * referenced by anything other than the font cache itself.
   * @return error status
   */
  NS_IMETHOD FlushFontCache(void) = 0;

  /**
   * Return the bit depth of the device.
   */
  NS_IMETHOD GetDepth(PRUint32& aDepth) = 0;

  /**
   * Return the image lib color space that's appropriate for this rendering
   * context.
   *
   * You must call IL_ReleaseSystemSpace() when you're done using the color space.
   */
  NS_IMETHOD GetILColorSpace(IL_ColorSpace*& aColorSpace) = 0;

  /**
   * Returns information about the device's palette capabilities.
   */
  NS_IMETHOD GetPaletteInfo(nsPaletteInfo&) = 0;

  /**
   * Returns Platform specific pixel value for an RGB value
   */
  NS_IMETHOD ConvertPixel(nscolor aColor, PRUint32 & aPixel) = 0;

  /**
   * Get the size of the displayable area of the output device
   * in app units.
   * @param aWidth out parameter for width
   * @param aHeight out parameter for height
   * @return error status
   */
  NS_IMETHOD GetDeviceSurfaceDimensions(PRInt32 &aWidth, PRInt32 &aHeight) = 0;

  /**
   * Returns a new nsIDeviceContext suitable for the device context
   * specification passed in.
   * @param aDevice a device context specification. this is a platform
   *        specific structure that only a platform specific device
   *        context can interpret.
   * @param aContext out parameter for new device context. nsnull on
   *        failure to create new device context.
   * @return error status
   */
  NS_IMETHOD GetDeviceContextFor(nsIDeviceContextSpec *aDevice,
                                 nsIDeviceContext *&aContext) = 0;

  //XXX need to work out re-entrancy issues for these APIs... MMP
  /**
   * Inform the output device that output of a document is beginning
   * Used for print related device contexts. Must be matched 1:1 with
   * EndDocument().
   * XXX needs to take parameters so that feedback can be given to the
   * app regarding pagination progress and aborting print operations?
   * @return error status
   */
  NS_IMETHOD BeginDocument(void) = 0;

  /**
   * Inform the output device that output of a document is ending.
   * Used for print related device contexts. Must be matched 1:1 with
   * BeginDocument()
   * @return error status
   */
  NS_IMETHOD EndDocument(void) = 0;

  /**
   * Inform the output device that output of a page is beginning
   * Used for print related device contexts. Must be matched 1:1 with
   * EndPage() and within a BeginDocument()/EndDocument() pair.
   * @return error status
   */
  NS_IMETHOD BeginPage(void) = 0;

  /**
   * Inform the output device that output of a page is ending
   * Used for print related device contexts. Must be matched 1:1 with
   * BeginPage() and within a BeginDocument()/EndDocument() pair.
   * @return error status
   */
  NS_IMETHOD EndPage(void) = 0;
};

#endif /* nsIDeviceContext_h___ */