1 /***************************************************************************
2 * Copyright (c) 2024 Microsoft Corporation
3 *
4 * This program and the accompanying materials are made available under the
5 * terms of the MIT License which is available at
6 * https://opensource.org/licenses/MIT.
7 *
8 * SPDX-License-Identifier: MIT
9 **************************************************************************/
10
11
12 /**************************************************************************/
13 /**************************************************************************/
14 /** */
15 /** GUIX Component */
16 /** */
17 /** Display Management (Display) */
18 /** */
19 /**************************************************************************/
20
21
22 #define PIXEL_WRITE(loc, val) (*(loc) = ((USHORT)val))
23
24 #define GX_SOURCE_CODE
25
26 /* Include necessary system files. */
27
28 #include "gx_api.h"
29 #include "gx_utility.h"
30 #include "gx_display.h"
31
32 #if defined (GX_BRUSH_ALPHA_SUPPORT)
33 /**************************************************************************/
34 /* */
35 /* FUNCTION RELEASE */
36 /* */
37 /* _gx_display_driver_simple_line_alpha_draw PORTABLE C */
38 /* 6.1 */
39 /* AUTHOR */
40 /* */
41 /* Kenneth Maxwell, Microsoft Corporation */
42 /* */
43 /* DESCRIPTION */
44 /* */
45 /* Generic driver function that handles drawing lines with brush */
46 /* alpha. */
47 /* */
48 /* INPUT */
49 /* */
50 /* context Drawing context */
51 /* xstart x-coord of endpoint */
52 /* ystart y-coord of endpoint */
53 /* xend x-coord of endpoint */
54 /* yend y-coord of endpoint */
55 /* */
56 /* OUTPUT */
57 /* */
58 /* None */
59 /* */
60 /* CALLS */
61 /* */
62 /* GX_ABS Compute the absolute value */
63 /* GX_SWAP_VALUE Swap two values */
64 /* [PIXEL_WRITE] Driver level pixel write */
65 /* routine */
66 /* [gx_display_driver_pixel_blend] Basic display driver pixel */
67 /* blend function */
68 /* */
69 /* CALLED BY */
70 /* */
71 /* GUIX Internal Code */
72 /* */
73 /* RELEASE HISTORY */
74 /* */
75 /* DATE NAME DESCRIPTION */
76 /* */
77 /* 05-19-2020 Kenneth Maxwell Initial Version 6.0 */
78 /* 09-30-2020 Kenneth Maxwell Modified comment(s), */
79 /* resulting in version 6.1 */
80 /* */
81 /**************************************************************************/
_gx_display_driver_simple_line_alpha_draw(GX_DRAW_CONTEXT * context,INT xstart,INT ystart,INT xend,INT yend,GX_UBYTE alpha)82 VOID _gx_display_driver_simple_line_alpha_draw(GX_DRAW_CONTEXT *context, INT xstart, INT ystart, INT xend, INT yend, GX_UBYTE alpha)
83 {
84 INT curx;
85 INT cury;
86 INT x_sign;
87 INT y_sign;
88 INT decision;
89 INT nextx;
90 INT nexty;
91 GX_POINT end_point;
92 GX_POINT mid_point;
93 GX_RECTANGLE half_rectangle;
94 GX_RECTANGLE half_over;
95 INT sign;
96 INT steps;
97 GX_BOOL clipped = GX_TRUE;
98 INT dx = GX_ABS(xend - xstart);
99 INT dy = GX_ABS(yend - ystart);
100
101 GX_RECTANGLE *clip = context -> gx_draw_context_clip;
102 GX_COLOR linecolor = context -> gx_draw_context_brush.gx_brush_line_color;
103 VOID (*blend_func)(GX_DRAW_CONTEXT *context, INT x, INT y, GX_COLOR fcolor, GX_UBYTE alpha);
104
105 blend_func = context -> gx_draw_context_display -> gx_display_driver_pixel_blend;
106
107 if (blend_func == GX_NULL)
108 {
109 return;
110 }
111
112 if (((dx >= dy && (xstart > xend)) || ((dy > dx) && ystart > yend)))
113 {
114 GX_SWAP_VALS(xend, xstart);
115 GX_SWAP_VALS(yend, ystart);
116 }
117 x_sign = (xend - xstart) / dx;
118 y_sign = (yend - ystart) / dy;
119
120 end_point.gx_point_x = (GX_VALUE)xstart;
121 end_point.gx_point_y = (GX_VALUE)ystart;
122
123 if (_gx_utility_rectangle_point_detect(clip, end_point))
124 {
125 end_point.gx_point_x = (GX_VALUE)xend;
126 end_point.gx_point_y = (GX_VALUE)yend;
127
128 if (_gx_utility_rectangle_point_detect(clip, end_point))
129 {
130 clipped = GX_FALSE;
131 }
132 }
133
134 if (clipped)
135 {
136 /* here if we must do clipping in the inner loop, because one
137 or both of the end points are outside clipping rectangle */
138
139 /* Calculate the middle point of the line. */
140 mid_point.gx_point_x = (GX_VALUE)((xend + xstart) >> 1);
141 mid_point.gx_point_y = (GX_VALUE)((yend + ystart) >> 1);
142
143 /* Judge the clip in which side. */
144 if (_gx_utility_rectangle_point_detect(clip, mid_point))
145 {
146
147 /* the clip in two sides. */
148 if (dx >= dy)
149 {
150 /* walk out the clipping point. */
151 for (curx = xstart, cury = ystart, decision = (dx >> 1); curx < mid_point.gx_point_x;
152 curx++, decision += dy)
153 {
154 if (decision >= dx)
155 {
156 decision -= dx;
157 cury += y_sign;
158 }
159
160 if (curx >= clip -> gx_rectangle_left &&
161 cury >= clip -> gx_rectangle_top &&
162 cury <= clip -> gx_rectangle_bottom)
163 {
164 break;
165 }
166 }
167 for (; curx <= mid_point.gx_point_x;
168 curx++, decision += dy)
169 {
170 if (decision >= dx)
171 {
172 decision -= dx;
173 cury += y_sign;
174 }
175
176 blend_func(context, curx, cury, linecolor, alpha);
177 }
178 for (nextx = xend, nexty = yend, decision = (dx >> 1); nextx > mid_point.gx_point_x;
179 nextx--, decision += dy)
180 {
181 if (decision >= dx)
182 {
183 decision -= dx;
184 nexty -= y_sign;
185 }
186 if (nextx <= clip -> gx_rectangle_right &&
187 nexty >= clip -> gx_rectangle_top &&
188 nexty <= clip -> gx_rectangle_bottom)
189 {
190 break;
191 }
192 }
193
194 for (; nextx > mid_point.gx_point_x;
195 nextx--, decision += dy)
196 {
197 if (decision >= dx)
198 {
199 decision -= dx;
200 nexty -= y_sign;
201 }
202 blend_func(context, nextx, nexty, linecolor, alpha);
203 }
204 }
205 else
206 {
207 for (nextx = xend, nexty = yend, decision = (dy >> 1); nexty > mid_point.gx_point_y;
208 nexty--, decision += dx)
209 {
210 if (decision >= dy)
211 {
212 decision -= dy;
213 nextx -= x_sign;
214 }
215 if (nextx >= clip -> gx_rectangle_left &&
216 nextx <= clip -> gx_rectangle_right &&
217 nexty <= clip -> gx_rectangle_bottom)
218 {
219 break;
220 }
221 }
222
223 for (; nexty > mid_point.gx_point_y;
224 nexty--, decision += dx)
225 {
226 if (decision >= dy)
227 {
228 decision -= dy;
229 nextx -= x_sign;
230 }
231 blend_func(context, nextx, nexty, linecolor, alpha);
232 }
233
234 /* walk out the clipping point. */
235 for (curx = xstart, cury = ystart, decision = (dy >> 1); cury < mid_point.gx_point_y;
236 cury++, decision += dx)
237 {
238 if (decision >= dy)
239 {
240 decision -= dy;
241 curx += x_sign;
242 }
243
244 if (curx >= clip -> gx_rectangle_left &&
245 curx <= clip -> gx_rectangle_right &&
246 cury >= clip -> gx_rectangle_top)
247 {
248 break;
249 }
250 }
251 for (; cury <= mid_point.gx_point_y;
252 cury++, decision += dx)
253 {
254 if (decision >= dy)
255 {
256 decision -= dy;
257 curx += x_sign;
258 }
259 blend_func(context, curx, cury, linecolor, alpha);
260 }
261 }
262 }
263 else
264 {
265 /* The clip stay at one side. */
266 if (dx >= dy)
267 {
268 half_rectangle.gx_rectangle_left = (GX_VALUE)xstart;
269 half_rectangle.gx_rectangle_right = mid_point.gx_point_x;
270 if (y_sign == 1)
271 {
272 half_rectangle.gx_rectangle_top = (GX_VALUE)ystart;
273 half_rectangle.gx_rectangle_bottom = mid_point.gx_point_y;
274 }
275 else
276 {
277 half_rectangle.gx_rectangle_top = mid_point.gx_point_y;
278 half_rectangle.gx_rectangle_bottom = (GX_VALUE)ystart;
279 }
280
281 if (_gx_utility_rectangle_overlap_detect(clip, &half_rectangle, &half_over))
282 {
283 curx = xstart;
284 cury = ystart;
285 steps = mid_point.gx_point_x - curx + 1;
286 sign = 1;
287 }
288 else
289 {
290 curx = xend;
291 cury = yend;
292 steps = xend - mid_point.gx_point_x;
293 sign = -1;
294 y_sign = 0 - y_sign;
295 }
296 for (decision = (dx >> 1); steps > 0; curx += sign, decision += dy, steps--)
297 {
298 if (decision >= dx)
299 {
300 decision -= dx;
301 cury += y_sign;
302 }
303
304 if (curx >= clip -> gx_rectangle_left &&
305 curx <= clip -> gx_rectangle_right &&
306 cury >= clip -> gx_rectangle_top &&
307 cury <= clip -> gx_rectangle_bottom)
308 {
309 blend_func(context, curx, cury, linecolor, alpha);
310 }
311 }
312 }
313 else
314 {
315 half_rectangle.gx_rectangle_top = (GX_VALUE)ystart;
316 half_rectangle.gx_rectangle_bottom = mid_point.gx_point_y;
317 if (x_sign == 1)
318 {
319 half_rectangle.gx_rectangle_right = mid_point.gx_point_x;
320 half_rectangle.gx_rectangle_left = (GX_VALUE)xstart;
321 }
322 else
323 {
324 half_rectangle.gx_rectangle_right = (GX_VALUE)xstart;
325 half_rectangle.gx_rectangle_left = mid_point.gx_point_x;
326 }
327
328 if (_gx_utility_rectangle_overlap_detect(clip, &half_rectangle, &half_over))
329 {
330 curx = xstart;
331 cury = ystart;
332 steps = mid_point.gx_point_y - cury + 1;
333 sign = 1;
334 }
335 else
336 {
337 curx = xend;
338 cury = yend;
339 steps = yend - mid_point.gx_point_y;
340 sign = -1;
341 x_sign = 0 - x_sign;
342 }
343
344 for (decision = (dy >> 1); steps > 0; cury += sign, decision += dx, steps--)
345 {
346 if (decision >= dy)
347 {
348 decision -= dy;
349 curx += x_sign;
350 }
351 if (curx >= clip -> gx_rectangle_left &&
352 curx <= clip -> gx_rectangle_right &&
353 cury >= clip -> gx_rectangle_top &&
354 cury <= clip -> gx_rectangle_bottom)
355 {
356 blend_func(context, curx, cury, linecolor, alpha);
357 }
358 }
359 }
360 }
361 }
362 else
363 {
364 /* here if both line ends lie within clipping rectangle, we can
365 run a faster inner loop */
366 if (dx >= dy)
367 {
368 for (curx = xstart, cury = ystart, nextx = xend, nexty = yend,
369 decision = (dx >> 1); curx <= nextx; curx++, nextx--,
370 decision += dy)
371 {
372
373 if (decision >= dx)
374 {
375 decision -= dx;
376 cury += y_sign;
377 nexty -= y_sign;
378
379 }
380 blend_func(context, curx, cury, linecolor, alpha);
381 blend_func(context, nextx, nexty, linecolor, alpha);
382 }
383 }
384 else
385 {
386
387 for (curx = xstart, cury = ystart, nextx = xend, nexty = yend,
388 decision = (dy >> 1); cury <= nexty; cury++, nexty--,
389 decision += dx)
390 {
391 if (decision >= dy)
392 {
393 decision -= dy;
394 curx += x_sign;
395 nextx -= x_sign;
396 }
397 blend_func(context, curx, cury, linecolor, alpha);
398 blend_func(context, nextx, nexty, linecolor, alpha);
399 }
400 }
401 }
402 }
403
404 #endif /* GX_BRUSH_ALPHA_SUPPORT */
405
