1 // -*- C++ -*-
2 /**
3  * \file Painter.h
4  * This file is part of LyX, the document processor.
5  * Licence details can be found in the file COPYING.
6  *
7  * \author unknown
8  * \author John Levon
9  *
10  * Full author contact details are available in file CREDITS.
11  */
12 
13 #ifndef PAINTER_H
14 #define PAINTER_H
15 
16 #include "support/strfwd.h"
17 #include "support/types.h"
18 
19 namespace lyx {
20 
21 class Font;
22 class FontInfo;
23 
24 namespace graphics { class Image; }
25 
26 namespace frontend {
27 
28 /**
29  * Painter - A painter class to encapsulate all graphics parameters and operations
30  *
31  * Every graphics operation in LyX should be made by this class. The
32  * painter is used for drawing on the WorkArea, and is passed around
33  * during draw operations.
34  *
35  * It hides low level windows system parameters so insets and other
36  * clients don't have to worry about them and we can control graphics and
37  * GUI toolkit dependent drawing functions inside this single class.
38  *
39  * The intention for a toolkit is that it uses these methods to paint
40  * onto a backing pixmap. Only when expose events arrive via the event
41  * queue, does the copy onto the actual WorkArea widget take place.
42  *
43  * Caution: All char_type and docstring arguments of the text drawing
44  * methods of this class are no UCS4 chars or strings if the font is a
45  * symbol font. They simply denote the code points of the font instead.
46  * You have to keep this in mind when you implement the methods in a
47  * frontend. You must not pass these parameters to a unicode conversion
48  * function in particular.
49  */
50 class Painter {
51 public:
Painter(double pixel_ratio)52 	Painter(double pixel_ratio) : pixel_ratio_(pixel_ratio) {}
53 
54 	static const int thin_line;
55 
56 	/// possible line styles
57 	enum line_style {
58 		line_solid, //< solid line
59 		line_solid_aliased, //< solid line, no anti-aliasing (used as a
60 		                    // workaround to painting issues)
61 		line_onoffdash //< dashes with spaces
62 	};
63 
64 	/// possible fill styles
65 	enum fill_style {
66 		fill_none,
67 		fill_oddeven,
68 		fill_winding
69 	};
70 
71 	/// possible character styles of preedit string.
72 	/// This is used for CJK input method support.
73 	enum preedit_style {
74 		preedit_default, //< when unselecting, no cursor and dashed underline.
75 		preedit_selecting, //< when selecting.
76 		preedit_cursor //< with cursor.
77 	};
78 
~Painter()79 	virtual ~Painter() {}
80 
81 	/// draw a line from point to point
82 	virtual void line(int x1, int y1, int x2, int y2, Color,
83 		line_style = line_solid, int line_width = thin_line) = 0;
84 
85 	/**
86 	 * lines -  draw a set of lines
87 	 * @param xp array of points' x co-ords
88 	 * @param yp array of points' y co-ords
89 	 * @param np size of the points array
90 	 */
91 	virtual void lines(int const * xp, int const * yp, int np, Color,
92 		fill_style = fill_none, line_style = line_solid,
93 		int line_width = thin_line) = 0;
94 
95 	/**
96 	 * path -  draw a path with bezier curves
97 	 * @param xp array of points' x co-ords
98 	 * @param yp array of points' y co-ords
99 	 * @param c1x array of first control points' x co-ords
100 	 * @param c1y array of first control points' y co-ords
101 	 * @param c2x array of second control points' x co-ords
102 	 * @param c2y array of second control points' y co-ords
103 	 * @param np size of the points array
104 	 */
105 	virtual void path(int const * xp, int const * yp,
106 		int const * c1x, int const * c1y,
107 		int const * c2x, int const * c2y,
108 		int np, Color,
109 		fill_style = fill_none, line_style = line_solid,
110 		int line_width = thin_line) = 0;
111 
112 	/// draw a rectangle
113 	virtual void rectangle(int x, int y, int w, int h, Color,
114 		line_style = line_solid, int line_width = thin_line) = 0;
115 
116 	/// draw a filled rectangle
117 	virtual void fillRectangle(int x, int y, int w, int h, Color) = 0;
118 
119 	/// draw an arc
120 	virtual void arc(int x, int y, unsigned int w, unsigned int h,
121 		int a1, int a2, Color) = 0;
122 
123 	/// draw a pixel
124 	virtual void point(int x, int y, Color) = 0;
125 
126 	/// draw an image from the image cache
127 	virtual void image(int x, int y, int w, int h,
128 		graphics::Image const & image) = 0;
129 
130 	/// draw a string at position x, y (y is the baseline).
131 	virtual void text(int x, int y, docstring const & str, FontInfo const & f) = 0;
132 
133 	/// draw a char at position x, y (y is the baseline)
134 	virtual void text(int x, int y, char_type c, FontInfo const & f) = 0;
135 
136 	/** draw a string at position x, y (y is the baseline). The
137 	 * text direction is enforced by the \c Font.
138 	 */
139 	virtual void text(int x, int y, docstring const & str, Font const & f,
140                       double wordspacing, double textwidth) = 0;
141 
142 	/** draw a string at position x, y (y is the baseline), but
143 	 * make sure that the part between \c from and \c to is in
144 	 * \c other color. The text direction is enforced by the \c Font.
145 	 */
146 	virtual void text(int x, int y, docstring const & str, Font const & f,
147 	                  Color other, size_type from, size_type to,
148                       double wordspacing, double textwidth) = 0;
149 
150 	// Returns true if the painter does not actually paint.
151 	virtual bool isNull() const = 0;
152 
pixelRatio()153 	double pixelRatio() const { return pixel_ratio_; }
154 
155 	/// draw the underbar, strikeout, xout, uuline and uwave font attributes
156 	virtual void textDecoration(FontInfo const & f, int x, int y, int width) = 0;
157 
158 	/**
159 	 * Draw a string and enclose it inside a rectangle. If
160 	 * back color is specified, the background is cleared with
161 	 * the given color. If frame is specified, a thin frame is drawn
162 	 * around the text with the given color.
163 	 */
164 	virtual void rectText(int x, int baseline, docstring const & str,
165 		FontInfo const & font, Color back, Color frame) = 0;
166 
167 	/// draw a string and enclose it inside a button frame
168 	virtual void buttonText(int x, int baseline, docstring const & s,
169 		FontInfo const & font, Color back, Color frame, int offset) = 0;
170 
171 	/// draw a character of a preedit string for cjk support.
172 	virtual int preeditText(int x, int y,
173 		char_type c, FontInfo const & f, preedit_style style) = 0;
174 
175 	/// start monochrome painting mode, i.e. map every color into [min,max]
176 	virtual void enterMonochromeMode(Color const & min,
177 		Color const & max) = 0;
178 	/// leave monochrome painting mode
179 	virtual void leaveMonochromeMode() = 0;
180 	/// draws a wavy line that can be used for underlining.
181 	virtual void wavyHorizontalLine(int x, int y, int width, ColorCode col) = 0;
182 private:
183 	/// Ratio between physical pixels and device-independent pixels
184 	double pixel_ratio_;
185 };
186 
187 } // namespace frontend
188 } // namespace lyx
189 
190 #endif // PAINTER_H
191