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      1 
      2 /*
      3  * Copyright 2006 The Android Open Source Project
      4  *
      5  * Use of this source code is governed by a BSD-style license that can be
      6  * found in the LICENSE file.
      7  */
      8 
      9 
     10 #ifndef SkTextBox_DEFINED
     11 #define SkTextBox_DEFINED
     12 
     13 #include "SkCanvas.h"
     14 
     15 /** \class SkTextBox
     16 
     17     SkTextBox is a helper class for drawing 1 or more lines of text
     18     within a rectangle. The textbox is positioned and clipped by its Frame.
     19     The Margin rectangle controls where the text is drawn relative to
     20     the Frame. Line-breaks occur inside the Margin rectangle.
     21 
     22     Spacing is a linear equation used to compute the distance between lines
     23     of text. Spacing consists of two scalars: mul and add, and the spacing
     24     between lines is computed as: spacing = paint.getTextSize() * mul + add
     25 */
     26 class SkTextBox {
     27 public:
     28     SkTextBox();
     29 
     30     enum Mode {
     31         kOneLine_Mode,
     32         kLineBreak_Mode,
     33 
     34         kModeCount
     35     };
     36     Mode    getMode() const { return (Mode)fMode; }
     37     void    setMode(Mode);
     38 
     39     enum SpacingAlign {
     40         kStart_SpacingAlign,
     41         kCenter_SpacingAlign,
     42         kEnd_SpacingAlign,
     43 
     44         kSpacingAlignCount
     45     };
     46     SpacingAlign    getSpacingAlign() const { return (SpacingAlign)fSpacingAlign; }
     47     void            setSpacingAlign(SpacingAlign);
     48 
     49     void    getBox(SkRect*) const;
     50     void    setBox(const SkRect&);
     51     void    setBox(SkScalar left, SkScalar top, SkScalar right, SkScalar bottom);
     52 
     53     void    getSpacing(SkScalar* mul, SkScalar* add) const;
     54     void    setSpacing(SkScalar mul, SkScalar add);
     55 
     56     void    draw(SkCanvas*, const char text[], size_t len, const SkPaint&);
     57 
     58     void    setText(const char text[], size_t len, const SkPaint&);
     59     void    draw(SkCanvas*);
     60     int     countLines() const;
     61     SkScalar getTextHeight() const;
     62 
     63     SkTextBlob* snapshotTextBlob(SkScalar* computedBottom) const;
     64 
     65     class Visitor {
     66     public:
     67         virtual ~Visitor() {}
     68         virtual void operator()(const char*, size_t, SkScalar x, SkScalar y, const SkPaint&) = 0;
     69     };
     70 
     71 private:
     72     SkRect      fBox;
     73     SkScalar    fSpacingMul, fSpacingAdd;
     74     uint8_t     fMode, fSpacingAlign;
     75     const char* fText;
     76     size_t      fLen;
     77     const SkPaint* fPaint;
     78 
     79     SkScalar visit(Visitor&, const char text[], size_t len, const SkPaint&) const;
     80 };
     81 
     82 class SkTextLineBreaker {
     83 public:
     84     static int CountLines(const char text[], size_t len, const SkPaint&, SkScalar width);
     85 };
     86 
     87 #endif
     88