include/pwlib/mcanvas.h

   1 /*
   2  * mcanvas.h
   3  *
   4  * Memory canvas.
   5  *
   6  * Portable Windows Library
   7  *
   8  * Copyright (c) 1993-1998 Equivalence Pty. Ltd.
   9  *
  10  * The contents of this file are subject to the Mozilla Public License
  11  * Version 1.0 (the "License"); you may not use this file except in
  12  * compliance with the License. You may obtain a copy of the License at
  13  * http://www.mozilla.org/MPL/
  14  *
  15  * Software distributed under the License is distributed on an "AS IS"
  16  * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
  17  * the License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * The Original Code is Portable Windows Library.
  21  *
  22  * The Initial Developer of the Original Code is Equivalence Pty. Ltd.
  23  *
  24  * Portions are Copyright (C) 1993 Free Software Foundation, Inc.
  25  * All Rights Reserved.
  26  *
  27  * Contributor(s): ______________________________________.
  28  *
  29  * $Log$
  30  * Revision 1.17  2001/05/22 12:49:33  robertj
  31  * Did some seriously wierd rewrite of platform headers to eliminate the
  32  *   stupid GNU compiler warning about braces not matching.
  33  *
  34  * Revision 1.16  1999/03/10 03:49:52  robertj
  35  * More documentation adjustments.
  36  *
  37  * Revision 1.15  1999/03/09 08:01:48  robertj
  38  * Changed comments for doc++ support (more to come).
  39  *
  40  * Revision 1.14  1999/02/16 08:08:45  robertj
  41  * MSVC 6.0 compatibility changes.
  42  *
  43  * Revision 1.13  1998/09/23 06:24:11  robertj
  44  * Added open source copyright license.
  45  *
  46  * Revision 1.12  1995/03/14 12:41:42  robertj
  47  * Updated documentation to use HTML codes.
  48  *
  49  * Revision 1.11  1994/12/21  11:53:14  robertj
  50  * Documentation and variable normalisation.
  51  *
  52  * Revision 1.10  1994/12/05  11:34:10  robertj
  53  * Major rewrite of images, pictures and pixmaps.
  54  * Renamed PPict, PPixels and PImage to make sure all uses are found.
  55  *
  56  * Revision 1.9  1994/08/23  11:32:52  robertj
  57  * Oops
  58  *
  59  * Revision 1.8  1994/08/22  00:46:48  robertj
  60  * Added pragma fro GNU C++ compiler.
  61  *
  62  * Revision 1.7  1994/06/25  11:55:15  robertj
  63  * Unix version synchronisation.
  64  *
  65  * Revision 1.6  1994/03/07  07:38:19  robertj
  66  * Major enhancementsacross the board.
  67  *
  68  * Revision 1.5  1994/01/03  04:42:23  robertj
  69  * Mass changes to common container classes and interactors etc etc etc.
  70  *
  71  * Revision 1.4  1993/10/16  20:33:20  robertj
  72  * Changed memory canvas to output to PImage which is no longer a bitmap.
  73  *
  74  * Revision 1.3  1993/08/21  01:50:33  robertj
  75  * Made Clone() function optional, default will assert if called.
  76  *
  77  * Revision 1.2  1993/07/14  12:49:16  robertj
  78  * Fixed RCS keywords.
  79  *
  80  */
  81
  82
  83 #define _PMEMORYCANVAS
  84
  85 #ifdef __GNUC__
  86 #pragma interface
  87 #endif
  88
  89
  90 /**A drawable area that will go to a \Ref{PImage} in memory. Note that the
  91    \Ref{PImage} object passed to the PMemoryCanvas is undefined while the
  92    PMemoryCanvas exists. Not until the PMemoryCanvas is destroyed is the
  93    \Ref{PImage} object guarenteed to be updated.
  94
  95   *********************************** NOTE ***********************************
  96   On Some platforms, canvases are a limited resource. Do NOT create and leave
  97   them around for long periods. As soon as it is not required till the next
  98   user event, destroy it!
  99   ****************************************************************************
 100  */
 101 class PMemoryCanvas : public PCanvas
 102 {
 103   PCLASSINFO(PMemoryCanvas, PCanvas);
 104
 105   public:
 106    /**Create a canvas using the specified image. The image will receive the
 107        drawing operations made to the canvas. The two types of images,
 108        \Ref{PPixelImage} and \Ref{PPictImage} will store the commands
 109        differently according to their internal representation of an image.
 110      */
 111     PMemoryCanvas(
 112       const PImage & img  /// Image to draw into.
 113     );
 114
 115       /** Destroy the canvas and image. */
 116     virtual ~PMemoryCanvas();
 117
 118
 119     /**@name Overrides from class PCanvas */
 120    /**Get the drawable area of the image, for instance, this would be the
 121        dimensions of the \Ref{PPixelImage} used by the canvas.
 122
 123        @return
 124        rectangle for the maximum size of the drawable area.
 125      */
 126     virtual PRect GetDrawingBounds() const;
 127
 128
 129     /**@name New functions for class */
 130    /**Get the image created by the canvas. While this will allow you to
 131        obtain a reference to the image instance being drawn to by the canvas,
 132        the state of the image is indeterminate while the PMemoryCanvas instance
 133        still exists. For example in X windows when a PPixelImage is being
 134        created, the pixels are not tranferred from the X server to the client
 135        until the PMemoryCanvas is destroyed.
 136      */
 137     const PImage GetImage();
 138
 139
 140   protected:
 141     /// Image to draw into.
 142     PImage image;
 143
 144     // New functions for class
 145     void Construct();
 146       // Internal function for common constructor code.
 147
 148
 149 // Include platform dependent part of class
 150 #include <pwlib/mcanvas.h>
 151 };
 152
 153
 154 // End Of File ///////////////////////////////////////////////////////////////