📄 minigui 体系结构之四 图形抽象层和输入抽象层及 native engine 的实现（一）.htm
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57 char* id;
58
59 // Initialization and termination
60 BOOL (*initgfx) (struct tagGFX* gfx);
61 void (*termgfx) (struct tagGFX* gfx);
62
63 // Phisical graphics context
64 GAL_GC phygc;
65 int bytes_per_phypixel;
66 int bits_per_phypixel;
67 int width_phygc;
68 int height_phygc;
69 int colors_phygc;
70 BOOL grayscale_screen;
71
72 // GC properties
73 int (*bytesperpixel) (GAL_GC gc);
74 int (*bitsperpixel) (GAL_GC gc);
75 int (*width) (GAL_GC gc);
76 int (*height) (GAL_GC gc);
77 int (*colors) (GAL_GC gc);
78
79 // Allocation and release of graphics context
80 int (*allocategc) (GAL_GC gc, int width, int height, int depth,
81 GAL_GC* newgc);
82 void (*freegc) (GAL_GC gc);
83 void (*setgc) (GAL_GC gc);
84
85 // Clipping of graphics context
86 void (*enableclipping) (GAL_GC gc);
87 void (*disableclipping) (GAL_GC gc);
88 int (*setclipping) (GAL_GC gc, int x1, int y1, int x2, int y2);
89 int (*getclipping) (GAL_GC gc, int* x1, int* y1, int* x2, int* y2);
90
91 // Background and foreground colors
92 int (*getbgcolor) (GAL_GC gc, gal_pixel* color);
93 int (*setbgcolor) (GAL_GC gc, gal_pixel color);
94 int (*getfgcolor) (GAL_GC gc, gal_pixel* color);
95 int (*setfgcolor) (GAL_GC gc, gal_pixel color);
96
97 // Convertion between gal_color and gal_pixel
98 gal_pixel (*mapcolor) (GAL_GC gc, gal_color *color);
99 int (*unmappixel) (GAL_GC gc, gal_pixel pixel, gal_color* color);
100 int (*packcolors) (GAL_GC gc, void* buf, gal_color* colors, int len);
101 int (*unpackpixels) (GAL_GC gc, void* buf, gal_color* colors, int len);
102
103 // Palette operations
104 int (*getpalette) (GAL_GC gc, int s, int len, gal_color* cmap);
105 int (*setpalette) (GAL_GC gc, int s, int len, gal_color* cmap);
106 int (*setcolorfulpalette) (GAL_GC gc);
107
108 // Box operations
109 size_t (*boxsize) (GAL_GC gc, int w, int h);
110 int (*fillbox) (GAL_GC gc, int x, int y, int w, int h,
111 gal_pixel pixel);
112 int (*putbox) (GAL_GC gc, int x, int y, int w, int h, void* buf);
113 int (*getbox) (GAL_GC gc, int x, int y, int w, int h, void* buf);
114 int (*putboxmask) (GAL_GC gc, int x, int y, int w, int h, void* buf, gal_pixel cxx);
115 int (*putboxpart) (GAL_GC gc, int x, int y, int w, int h, int bw,
116 int bh, void* buf, int xo, int yo);
117 int (*putboxwithop) (GAL_GC gc, int x, int y, int w, int h,
118 void* buf, int raster_op);
119 int (*scalebox) (GAL_GC gc, int sw, int sh, void* srcbuf,
120 int dw, int dh, void* dstbuf);
121
122 int (*copybox) (GAL_GC gc, int x, int y, int w, int h, int nx, int ny);
123 int (*crossblit) (GAL_GC src, int sx, int sy, int sw, int sh,
124 GAL_GC dst, int dx, int dy);
125
126 // Horizontal line operaions
127 int (*drawhline) (GAL_GC gc, int x, int y, int w, gal_pixel pixel);
128 int (*puthline) (GAL_GC gc, int x, int y, int w, void* buf);
129 int (*gethline) (GAL_GC gc, int x, int y, int w, void* buf);
130
131 // Vertical line operations
132 int (*drawvline) (GAL_GC gc, int x, int y, int h, gal_pixel pixel);
133 int (*putvline) (GAL_GC gc, int x, int y, int h, void* buf);
134 int (*getvline) (GAL_GC gc, int x, int y, int h, void* buf);
135
136 // Pixel operations
137 int (*drawpixel) (GAL_GC gc, int x, int y, gal_pixel pixel);
138 int (*putpixel) (GAL_GC gc, int x, int y, gal_pixel color);
139 int (*getpixel) (GAL_GC gc, int x, int y, gal_pixel* color);
140
141 // Other drawing
142 int (*circle) (GAL_GC gc, int x, int y, int r, gal_pixel pixel);
143 int (*line) (GAL_GC gc, int x1, int y1, int x2, int y2,
144 gal_pixel pixel);
145 int (*rectangle) (GAL_GC gc, int l, int t, int r, int b,
146 gal_pixel pixel);
147
148 // Simple Character output
149 int (*putchar) (GAL_GC gc, int x, int y, char c);
150 int (*putstr) (GAL_GC gc, int x, int y, const char* str);
151 int (*getcharsize) (GAL_GC gc, int* width, int* height);
152 int (*setputcharmode) (GAL_GC gc, int bkmode);
153 int (*setfontcolors) (GAL_GC gc,
154 gal_pixel fg, gal_pixel bg);
155
156 // Asynchronous mode support
157 void (*flush) (GAL_GC gc);
158 void (*flushregion) (GAL_GC gc, int x, int y, int w, int h);
159
160 // Panic
161 void (*panic) (int exitcode);
162
163 } GFX;
164
165 extern GFX* cur_gfx;
</PRE></TD></TR></TBODY></TABLE>
<P>系统启动之后，将根据配置寻找特定的图形引擎作为当前的图形引擎，并且对全局变量 cur_gfx 赋值。之后，当 MiniGUI
需要在屏幕上进行绘制之后，调用当前图形引擎的相应功能函数。比如，在画水平线时如下调用：</P>
<TABLE class=code-sample cellPadding=0 width="100%" border=0>
<TBODY>
<TR>
<TD><PRE>(*cur_gfx->drawhline) (gc, x, y, w, pixel);
</PRE></TD></TR></TBODY></TABLE>
<P>为方便程序书写，我们还定义了如下 C 语言宏：</P>
<TABLE class=code-sample cellPadding=0 width="100%" border=0>
<TBODY>
<TR>
<TD><PRE> 167 #define PHYSICALGC (cur_gfx->phygc)
168 #define BYTESPERPHYPIXEL (cur_gfx->bytes_per_phypixel)
169 #define BITSPERPHYPIXEL (cur_gfx->bits_per_phypixel)
170 #define WIDTHOFPHYGC (cur_gfx->width_phygc)
171 #define HEIGHTOFPHYGC (cur_gfx->height_phygc)
172 #define COLORSOFPHYGC (cur_gfx->colors_phygc)
173 #define GRAYSCALESCREEN (cur_gfx->grayscale_screen)
174
175 #define GAL_BytesPerPixel (*cur_gfx->bytesperpixel)
176 #define GAL_BitsPerPixel (*cur_gfx->bitsperpixel)
177 #define GAL_Width (*cur_gfx->width)
178 #define GAL_Height (*cur_gfx->height)
179 #define GAL_Colors (*cur_gfx->colors)
180
181 #define GAL_InitGfx (*cur_gfx->initgfx)
182 #define GAL_TermGfx (*cur_gfx->termgfx)
183
184 #define GAL_AllocateGC (*cur_gfx->allocategc)
185 #define GAL_FreeGC (*cur_gfx->freegc)
186
...
198
199 #define GAL_MapColor (*cur_gfx->mapcolor)
200 #define GAL_UnmapPixel (*cur_gfx->unmappixel)
201 #define GAL_PackColors (*cur_gfx->packcolors)
202 #define GAL_UnpackPixels (*cur_gfx->unpackpixels)
203
...
208 #define GAL_BoxSize (*cur_gfx->boxsize)
209 #define GAL_FillBox (*cur_gfx->fillbox)
210 #define GAL_PutBox (*cur_gfx->putbox)
211 #define GAL_GetBox (*cur_gfx->getbox)
212 #define GAL_PutBoxMask (*cur_gfx->putboxmask)
213 #define GAL_PutBoxPart (*cur_gfx->putboxpart)
214 #define GAL_PubBoxWithOp (*cur_gfx->putboxwithop)
215 #define GAL_ScaleBox (*cur_gfx->scalebox)
...
224 #define GAL_DrawVLine (*cur_gfx->drawvline)
225 #define GAL_PutVLine (*cur_gfx->putvline)
226 #define GAL_GetVLine (*cur_gfx->getvline)
</PRE></TD></TR></TBODY></TABLE>
<P>这样，上述画线函数可以如下书写：</P>
<TABLE class=code-sample cellPadding=0 width="100%" border=0>
<TBODY>
<TR>
<TD><PRE>GAL_DrawVLine (gc, x, y, w, pixel);
</PRE></TD></TR></TBODY></TABLE>
<P>显然，只要在系统初始化时能够根据设定对 cur_gfx 进行适当的赋值，MiniGUI 就能够在相应的图形引擎之上进行绘制。</P>
<P>对底层图形引擎的调用，主要集中在 MiniGUI 的 GDI 函数中。比如，要绘制一条直线，MiniGUI 的 LineTo 函数定义如清单
2 所示：</P>
<TABLE class=code-sample cellPadding=0 width="100%" border=0>
<TBODY>
<TR>
<TD><PRE> 清单 2 LineTo 函数（src/gdi/draw-lite.c）
255 void GUIAPI LineTo (HDC hdc, int x, int y)
256 {
257 PCLIPRECT pClipRect;
258 PDC pdc;
259 RECT rcOutput;
260 int startx, starty;
261
262 pdc = dc_HDC2PDC(hdc);
263
264 if (dc_IsGeneralHDC(hdc)) {
265 if (!dc_GenerateECRgn (pdc, FALSE)) {
266 return;
267 }
268 }
269
270 // Transfer logical to device to screen here.
271 startx = pdc->CurPenPos.x;
272 starty = pdc->CurPenPos.y;
273
274 // Move the current pen pos.
275 pdc->CurPenPos.x = x;
276 pdc->CurPenPos.y = y;
277
278 coor_LP2SP(pdc, &x, &y);
279 coor_LP2SP(pdc, &startx, &starty);
280 rcOutput.left = startx - 1;
281 rcOutput.top = starty - 1;
282 rcOutput.right = x + 1;
283 rcOutput.bottom = y + 1;
284 NormalizeRect(&rcOutput);
285
286 IntersectRect (&rcOutput, &rcOutput, &pdc->ecrgn.rcBound);
287 if( !dc_IsMemHDC(hdc) ) ShowCursorForGDI(FALSE, &rcOutput);
288
289 // set graphics context.
290 GAL_SetGC (pdc->gc);
291 GAL_SetFgColor (pdc->gc, pdc->pencolor);
292
293 pClipRect = pdc->ecrgn.head;
294 while(pClipRect)
295 {
296 if (DoesIntersect (&rcOutput, &pClipRect->rc)) {
297 GAL_SetClipping (pdc->gc, pClipRect->rc.left, pClipRect->rc.top,
298 pClipRect->rc.right - 1, pClipRect->rc.bottom - 1);
299
300 if(starty == y) {
301 if (startx > x)
302 GAL_DrawHLine (pdc->gc, x, y, startx - x, pdc->pencolor);
303 else
304 GAL_DrawHLine (pdc->gc, startx, y, x - startx, pdc->pencolor);
305 }
306 else
307 GAL_Line (pdc->gc, startx, starty, x, y, pdc->pencolor);
308 }
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