third_party/WebKit/public/web/WebFont.h

   1 /*
   2  * Copyright (C) 2010 Google Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  *     * Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *     * Redistributions in binary form must reproduce the above
  11  * copyright notice, this list of conditions and the following disclaimer
  12  * in the documentation and/or other materials provided with the
  13  * distribution.
  14  *     * Neither the name of Google Inc. nor the names of its
  15  * contributors may be used to endorse or promote products derived from
  16  * this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #ifndef WebFont_h
  32 #define WebFont_h
  33
  34 #include "../platform/WebCanvas.h"
  35 #include "../platform/WebColor.h"
  36 #include "../platform/WebCommon.h"
  37
  38 namespace blink {
  39
  40 struct WebFontDescription;
  41 struct WebFloatPoint;
  42 struct WebFloatRect;
  43 struct WebRect;
  44 struct WebTextRun;
  45
  46 class WebFont {
  47 public:
  48     virtual ~WebFont() { }
  49
  50     BLINK_EXPORT static WebFont* create(const WebFontDescription&);
  51
  52     virtual WebFontDescription fontDescription() const = 0;
  53
  54     virtual int ascent() const = 0;
  55     virtual int descent() const = 0;
  56     virtual int height() const = 0;
  57     virtual int lineSpacing() const = 0;
  58     virtual float xHeight() const = 0;
  59
  60     // Draws the text run to the given canvas. The text is positioned at the
  61     // given left-hand point at the baseline.
  62     //
  63     // The text will be clipped to the given clip rect.
  64     virtual void drawText(WebCanvas*, const WebTextRun&, const WebFloatPoint& leftBaseline, WebColor,
  65                           const WebRect& clip) const = 0;
  66
  67
  68     // Measures the width in pixels of the given text run.
  69     virtual int calculateWidth(const WebTextRun&) const = 0;
  70
  71     // Returns the character offset corresponding to the given horizontal pixel
  72     // position as measured from from the left of the run.
  73     virtual int offsetForPosition(const WebTextRun&, float position) const = 0;
  74
  75     // Returns the rectangle representing the selection rect for the subrange
  76     // |from| -> |to| of the given text run. You can use -1 for |to| to specify
  77     // the entire run (this will do something similar to calling width()).
  78     //
  79     // The rect will be positioned as if the text was drawn at the given
  80     // |leftBaseline| position. |height| indicates the height of the selection
  81     // rect you want, typically this will just be the height() of this font.
  82     //
  83     // To get the pixel offset of some character (the opposite of
  84     // offsetForPosition()), pass in a |leftBaseline| = (0, 0), |from| = 0, and
  85     // |to| = the character you want. The right edge of the resulting selection
  86     // rect will tell you the right side of the character.
  87     virtual WebFloatRect selectionRectForText(const WebTextRun&, const WebFloatPoint& leftBaseline,
  88                                               int height, int from = 0, int to = -1) const = 0;
  89 };
  90
  91 } // namespace blink
  92
  93 #endif