xref: /illumos-gate/usr/src/common/ficl/emu/gfx_fb.c (revision 12fb9219923f41528f673d4f31667db2c3f103ff)
1 /*
2  * This file and its contents are supplied under the terms of the
3  * Common Development and Distribution License ("CDDL"), version 1.0.
4  * You may only use this file in accordance with the terms of version
5  * 1.0 of the CDDL.
6  *
7  * A full copy of the text of the CDDL should have accompanied this
8  * source.  A copy of the CDDL is also available via the Internet at
9  * http://www.illumos.org/license/CDDL.
10  */
11 
12 /*
13  * Copyright 2016 Toomas Soome <tsoome@me.com>
14  */
15 
16 /*
17  * Graphics support for loader emulation.
18  * The interface in loader and here needs some more development.
19  * We can get colormap from gfx_private, but loader is currently
20  * relying on tem fg/bg colors for drawing, once the menu code
21  * will get some facelift, we would need to provide colors as menu component
22  * attributes and stop depending on tem.
23  */
24 
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <stdbool.h>
28 #include <sys/types.h>
29 #include <sys/stat.h>
30 #include <fcntl.h>
31 #include <unistd.h>
32 #include <sys/mman.h>
33 #include <sys/fbio.h>
34 #include <string.h>
35 #include "gfx_fb.h"
36 
37 struct framebuffer fb;
38 
39 #define	max(x, y)	((x) >= (y) ? (x) : (y))
40 
41 static void gfx_fb_cons_display(uint32_t, uint32_t,
42     uint32_t, uint32_t, uint8_t *);
43 
44 /* This colormap should be replaced by colormap query from kernel */
45 typedef struct {
46 	uint8_t red[16];
47 	uint8_t green[16];
48 	uint8_t blue[16];
49 } text_cmap_t;
50 
51 text_cmap_t cmap4_to_24 = {
52 /* BEGIN CSTYLED */
53 /*             0    1    2    3    4    5    6    7    8    9   10   11   12   13   14   15
54               Wh+  Bk   Bl   Gr   Cy   Rd   Mg   Br   Wh   Bk+  Bl+  Gr+  Cy+  Rd+  Mg+  Yw */
55   .red   = {0xff,0x00,0x00,0x00,0x00,0x80,0x80,0x80,0x80,0x40,0x00,0x00,0x00,0xff,0xff,0xff},
56   .green = {0xff,0x00,0x00,0x80,0x80,0x00,0x00,0x80,0x80,0x40,0x00,0xff,0xff,0x00,0x00,0xff},
57   .blue  = {0xff,0x00,0x80,0x00,0x80,0x00,0x80,0x00,0x80,0x40,0xff,0x00,0xff,0x00,0xff,0x00}
58 /* END CSTYLED */
59 };
60 
61 const uint8_t solaris_color_to_pc_color[16] = {
62     15, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14
63 };
64 
65 void
66 gfx_framework_init(void)
67 {
68 	struct fbgattr attr;
69 	struct gfxfb_info *gfxfb_info;
70 	char buf[10];
71 
72 	fb.fd = open("/dev/fb", O_RDWR);
73 	if (fb.fd < 0)
74 		return;
75 
76 	/* make sure we have GFX framebuffer */
77 	if (ioctl(fb.fd, VIS_GETIDENTIFIER, &fb.ident) < 0 ||
78 	    strcmp(fb.ident.name, "illumos_fb") != 0) {
79 		(void) close(fb.fd);
80 		fb.fd = -1;
81 		return;
82 	}
83 
84 	if (ioctl(fb.fd, FBIOGATTR, &attr) < 0) {
85 		(void) close(fb.fd);
86 		fb.fd = -1;
87 		return;
88 	}
89 	gfxfb_info = (struct gfxfb_info *)attr.sattr.dev_specific;
90 
91 	fb.fb_height = attr.fbtype.fb_height;
92 	fb.fb_width = attr.fbtype.fb_width;
93 	fb.fb_depth = attr.fbtype.fb_depth;
94 	fb.fb_size = attr.fbtype.fb_size;
95 	fb.fb_bpp = attr.fbtype.fb_depth >> 3;
96 	if (attr.fbtype.fb_depth == 15)
97 		fb.fb_bpp = 2;
98 	fb.fb_pitch = gfxfb_info->pitch;
99 	fb.terminal_origin_x = gfxfb_info->terminal_origin_x;
100 	fb.terminal_origin_y = gfxfb_info->terminal_origin_y;
101 	fb.font_width = gfxfb_info->font_width;
102 	fb.font_height = gfxfb_info->font_height;
103 
104 	fb.red_mask_size = gfxfb_info->red_mask_size;
105 	fb.red_field_position = gfxfb_info->red_field_position;
106 	fb.green_mask_size = gfxfb_info->green_mask_size;
107 	fb.green_field_position = gfxfb_info->green_field_position;
108 	fb.blue_mask_size = gfxfb_info->blue_mask_size;
109 	fb.blue_field_position = gfxfb_info->blue_field_position;
110 
111 	fb.fb_addr = (uint8_t *)mmap(0, fb.fb_size, (PROT_READ | PROT_WRITE),
112 	    MAP_SHARED, fb.fd, 0);
113 
114 	if (fb.fb_addr == NULL) {
115 		(void) close(fb.fd);
116 		fb.fd = -1;
117 		return;
118 	}
119 	(void) snprintf(buf, sizeof (buf), "%d", fb.fb_height);
120 	(void) setenv("screen-height", buf, 1);
121 	(void) snprintf(buf, sizeof (buf), "%d", fb.fb_width);
122 	(void) setenv("screen-width", buf, 1);
123 }
124 
125 void
126 gfx_framework_fini(void)
127 {
128 	if (fb.fd < 0)
129 		return;
130 
131 	(void) munmap((caddr_t)fb.fb_addr, fb.fb_size);
132 	(void) close(fb.fd);
133 	fb.fd = -1;
134 }
135 
136 static int
137 isqrt(int num)
138 {
139 	int res = 0;
140 	int bit = 1 << 30;
141 
142 	/* "bit" starts at the highest power of four <= the argument. */
143 	while (bit > num)
144 		bit >>= 2;
145 
146 	while (bit != 0) {
147 		if (num >= res + bit) {
148 			num -= res + bit;
149 			res = (res >> 1) + bit;
150 		} else {
151 			res >>= 1;
152 		}
153 		bit >>= 2;
154 	}
155 	return (res);
156 }
157 
158 void
159 gfx_fb_setpixel(uint32_t x, uint32_t y)
160 {
161 	uint32_t c, offset;
162 
163 	if (fb.fd < 0)
164 		return;
165 	c = 0;		/* black */
166 
167 	if (x >= fb.fb_width || y >= fb.fb_height)
168 		return;
169 
170 	offset = y * fb.fb_pitch + x * fb.fb_bpp;
171 	switch (fb.fb_depth) {
172 	case 8:
173 		fb.fb_addr[offset] = c & 0xff;
174 		break;
175 	case 15:
176 	case 16:
177 		*(uint16_t *)(fb.fb_addr + offset) = c & 0xffff;
178 		break;
179 	case 24:
180 		fb.fb_addr[offset] = (c >> 16) & 0xff;
181 		fb.fb_addr[offset + 1] = (c >> 8) & 0xff;
182 		fb.fb_addr[offset + 2] = c & 0xff;
183 		break;
184 	case 32:
185 		*(uint32_t *)(fb.fb_addr + offset) = c;
186 		break;
187 	}
188 }
189 
190 void
191 gfx_fb_drawrect(uint32_t x1, uint32_t y1, uint32_t x2, uint32_t y2,
192     uint32_t fill)
193 {
194 	int x, y;
195 
196 	if (fb.fd < 0)
197 		return;
198 
199 	for (y = y1; y <= y2; y++) {
200 		if (fill || (y == y1) || (y == y2)) {
201 			for (x = x1; x <= x2; x++)
202 				gfx_fb_setpixel(x, y);
203 		} else {
204 			gfx_fb_setpixel(x1, y);
205 			gfx_fb_setpixel(x2, y);
206 		}
207 	}
208 }
209 
210 void
211 gfx_term_drawrect(uint32_t row1, uint32_t col1, uint32_t row2, uint32_t col2)
212 {
213 	int x1, y1, x2, y2;
214 	int xshift, yshift;
215 	int width, i;
216 
217 	if (fb.fd < 0)
218 		return;
219 
220 	width = fb.font_width / 4;	/* line width */
221 	xshift = (fb.font_width - width) / 2;
222 	yshift = (fb.font_height - width) / 2;
223 	/* Terminal coordinates start from (1,1) */
224 	row1--;
225 	col1--;
226 	row2--;
227 	col2--;
228 
229 	/*
230 	 * Draw horizontal lines width points thick, shifted from outer edge.
231 	 */
232 	x1 = (row1 + 1) * fb.font_width + fb.terminal_origin_x;
233 	y1 = col1 * fb.font_height + fb.terminal_origin_y + yshift;
234 	x2 = row2 * fb.font_width + fb.terminal_origin_x;
235 	gfx_fb_drawrect(x1, y1, x2, y1 + width, 1);
236 	y2 = col2 * fb.font_height + fb.terminal_origin_y;
237 	y2 += fb.font_height - yshift - width;
238 	gfx_fb_drawrect(x1, y2, x2, y2 + width, 1);
239 
240 	/*
241 	 * Draw vertical lines width points thick, shifted from outer edge.
242 	 */
243 	x1 = row1 * fb.font_width + fb.terminal_origin_x + xshift;
244 	y1 = col1 * fb.font_height + fb.terminal_origin_y;
245 	y1 += fb.font_height;
246 	y2 = col2 * fb.font_height + fb.terminal_origin_y;
247 	gfx_fb_drawrect(x1, y1, x1 + width, y2, 1);
248 	x1 = row2 * fb.font_width + fb.terminal_origin_x;
249 	x1 += fb.font_width - xshift - width;
250 	gfx_fb_drawrect(x1, y1, x1 + width, y2, 1);
251 
252 	/* Draw upper left corner. */
253 	x1 = row1 * fb.font_width + fb.terminal_origin_x + xshift;
254 	y1 = col1 * fb.font_height + fb.terminal_origin_y;
255 	y1 += fb.font_height;
256 
257 	x2 = row1 * fb.font_width + fb.terminal_origin_x;
258 	x2 += fb.font_width;
259 	y2 = col1 * fb.font_height + fb.terminal_origin_y + yshift;
260 	for (i = 0; i <= width; i++)
261 		gfx_fb_bezier(x1 + i, y1, x1 + i, y2 + i, x2, y2 + i, width-i);
262 
263 	/* Draw lower left corner. */
264 	x1 = row1 * fb.font_width + fb.terminal_origin_x;
265 	x1 += fb.font_width;
266 	y1 = col2 * fb.font_height + fb.terminal_origin_y;
267 	y1 += fb.font_height - yshift;
268 	x2 = row1 * fb.font_width + fb.terminal_origin_x + xshift;
269 	y2 = col2 * fb.font_height + fb.terminal_origin_y;
270 	for (i = 0; i <= width; i++)
271 		gfx_fb_bezier(x1, y1 - i, x2 + i, y1 - i, x2 + i, y2, width-i);
272 
273 	/* Draw upper right corner. */
274 	x1 = row2 * fb.font_width + fb.terminal_origin_x;
275 	y1 = col1 * fb.font_height + fb.terminal_origin_y + yshift;
276 	x2 = row2 * fb.font_width + fb.terminal_origin_x;
277 	x2 += fb.font_width - xshift - width;
278 	y2 = col1 * fb.font_height + fb.terminal_origin_y;
279 	y2 += fb.font_height;
280 	for (i = 0; i <= width; i++)
281 		gfx_fb_bezier(x1, y1 + i, x2 + i, y1 + i, x2 + i, y2, width-i);
282 
283 	/* Draw lower right corner. */
284 	x1 = row2 * fb.font_width + fb.terminal_origin_x;
285 	y1 = col2 * fb.font_height + fb.terminal_origin_y;
286 	y1 += fb.font_height - yshift;
287 	x2 = row2 * fb.font_width + fb.terminal_origin_x;
288 	x2 += fb.font_width - xshift - width;
289 	y2 = col2 * fb.font_height + fb.terminal_origin_y;
290 	for (i = 0; i <= width; i++)
291 		gfx_fb_bezier(x1, y1 - i, x2 + i, y1 - i, x2 + i, y2, width-i);
292 }
293 
294 void
295 gfx_fb_line(uint32_t x0, uint32_t y0, uint32_t x1, uint32_t y1, uint32_t width)
296 {
297 	int dx, sx, dy, sy;
298 	int err, e2, x2, y2, ed;
299 
300 	if (fb.fd < 0)
301 		return;
302 
303 	sx = x0 < x1? 1 : -1;
304 	sy = y0 < y1? 1 : -1;
305 	dx = abs(x1 - x0);
306 	dy = abs(y1 - y0);
307 	err = dx - dy;
308 	ed = dx + dy == 0 ? 1 : isqrt(dx * dx + dy * dy);
309 
310 	if (dx != 0 && dy != 0)
311 		width = (width + 1) >> 1;
312 
313 	for (;;) {
314 		gfx_fb_setpixel(x0, y0);
315 		e2 = err;
316 		x2 = x0;
317 		if ((e2 << 1) >= -dx) {		/* x step */
318 			e2 += dy;
319 			y2 = y0;
320 			while (e2 < ed * width && (y1 != y2 || dx > dy)) {
321 				y2 += sy;
322 				gfx_fb_setpixel(x0, y2);
323 				e2 += dx;
324 			}
325 			if (x0 == x1)
326 				break;
327 			e2 = err;
328 			err -= dy;
329 			x0 += sx;
330 		}
331 		if ((e2 << 1) <= dy) {		/* y step */
332 			e2 = dx-e2;
333 			while (e2 < ed * width && (x1 != x2 || dx < dy)) {
334 				x2 += sx;
335 				gfx_fb_setpixel(x2, y0);
336 				e2 += dy;
337 			}
338 			if (y0 == y1)
339 				break;
340 			err += dx;
341 			y0 += sy;
342 		}
343 	}
344 }
345 
346 void
347 gfx_fb_bezier(uint32_t x0, uint32_t y0, uint32_t x1, uint32_t y1, uint32_t x2,
348     uint32_t y2, uint32_t wd)
349 {
350 	int sx, sy, xx, yy, xy, width;
351 	int dx, dy, err, curvature;
352 	int i;
353 
354 	if (fb.fd < 0)
355 		return;
356 
357 	width = wd;
358 	sx = x2 - x1;
359 	sy = y2 - y1;
360 	xx = x0 - x1;
361 	yy = y0 - y1;
362 	curvature = xx*sy - yy*sx;
363 
364 	if (sx * sx + sy * sy > xx * xx + yy * yy) {
365 		x2 = x0;
366 		x0 = sx + x1;
367 		y2 = y0;
368 		y0 = sy + y1;
369 		curvature = -curvature;
370 	}
371 	if (curvature != 0) {
372 		xx += sx;
373 		sx = x0 < x2? 1 : -1;
374 		xx *= sx;
375 		yy += sy;
376 		sy = y0 < y2? 1 : -1;
377 		yy *= sy;
378 		xy = 2 * xx * yy;
379 		xx *= xx;
380 		yy *= yy;
381 		if (curvature * sx * sy < 0) {
382 			xx = -xx;
383 			yy = -yy;
384 			xy = -xy;
385 			curvature = -curvature;
386 		}
387 		dx = 4 * sy * curvature * (x1 - x0) + xx - xy;
388 		dy = 4 * sx * curvature * (y0 - y1) + yy - xy;
389 		xx += xx;
390 		yy += yy;
391 		err = dx + dy + xy;
392 		do {
393 			for (i = 0; i <= width; i++)
394 				gfx_fb_setpixel(x0 + i, y0);
395 			if (x0 == x2 && y0 == y2)
396 				return;  /* last pixel -> curve finished */
397 			y1 = 2 * err < dx;
398 			if (2 * err > dy) {
399 				x0 += sx;
400 				dx -= xy;
401 				dy += yy;
402 				err += dy;
403 			}
404 			if (y1 != 0) {
405 				y0 += sy;
406 				dy -= xy;
407 				dx += xx;
408 				err += dx;
409 			}
410 		} while (dy < dx); /* gradient negates -> algorithm fails */
411 	}
412 	gfx_fb_line(x0, y0, x2, y2, width);
413 }
414 
415 #define	FL_PUTIMAGE_BORDER	0x1
416 #define	FL_PUTIMAGE_NOSCROLL	0x2
417 #define	FL_PUTIMAGE_DEBUG	0x80
418 
419 int
420 gfx_fb_putimage(png_t *png, uint32_t ux1, uint32_t uy1, uint32_t ux2,
421     uint32_t uy2, uint32_t flags)
422 {
423 	uint32_t i, j, x, y, fheight, fwidth, color;
424 	uint8_t r, g, b, a, *p, *data;
425 	bool scale = false;
426 	bool trace = false;
427 
428 	trace = (flags & FL_PUTIMAGE_DEBUG) != 0;
429 
430 	if (fb.fd < 0) {
431 		if (trace)
432 			printf("Framebuffer not active.\n");
433 		return (1);
434 	}
435 
436 	if (png->color_type != PNG_TRUECOLOR_ALPHA) {
437 		if (trace)
438 			printf("Not truecolor image.\n");
439 		return (1);
440 	}
441 
442 	if (ux1 > fb.fb_width || uy1 > fb.fb_height) {
443 		if (trace)
444 			printf("Top left coordinate off screen.\n");
445 		return (1);
446 	}
447 
448 	if (png->width > UINT16_MAX || png->height > UINT16_MAX) {
449 		if (trace)
450 			printf("Image too large.\n");
451 		return (1);
452 	}
453 
454 	if (png->width < 1 || png->height < 1) {
455 		if (trace)
456 			printf("Image too small.\n");
457 		return (1);
458 	}
459 
460 	/*
461 	 * If 0 was passed for either ux2 or uy2, then calculate the missing
462 	 * part of the bottom right coordinate.
463 	 */
464 	scale = true;
465 	if (ux2 == 0 && uy2 == 0) {
466 		/* Both 0, use the native resolution of the image */
467 		ux2 = ux1 + png->width;
468 		uy2 = uy1 + png->height;
469 		scale = false;
470 	} else if (ux2 == 0) {
471 		/* Set ux2 from uy2/uy1 to maintain aspect ratio */
472 		ux2 = ux1 + (png->width * (uy2 - uy1)) / png->height;
473 	} else if (uy2 == 0) {
474 		/* Set uy2 from ux2/ux1 to maintain aspect ratio */
475 		uy2 = uy1 + (png->height * (ux2 - ux1)) / png->width;
476 	}
477 
478 	if (ux2 > fb.fb_width || uy2 > fb.fb_height) {
479 		if (trace)
480 			printf("Bottom right coordinate off screen.\n");
481 		return (1);
482 	}
483 
484 	fwidth = ux2 - ux1;
485 	fheight = uy2 - uy1;
486 
487 	/*
488 	 * If the original image dimensions have been passed explicitly,
489 	 * disable scaling.
490 	 */
491 	if (fwidth == png->width && fheight == png->height)
492 		scale = false;
493 
494 	if (ux1 == 0) {
495 		/*
496 		 * No top left X co-ordinate (real coordinates start at 1),
497 		 * place as far right as it will fit.
498 		 */
499 		ux2 = fb.fb_width - fb.terminal_origin_x;
500 		ux1 = ux2 - fwidth;
501 	}
502 
503 	if (uy1 == 0) {
504 		/*
505 		 * No top left Y co-ordinate (real coordinates start at 1),
506 		 * place as far down as it will fit.
507 		 */
508 		uy2 = fb.fb_height - fb.terminal_origin_y;
509 		uy1 = uy2 - fheight;
510 	}
511 
512 	if (ux1 >= ux2 || uy1 >= uy2) {
513 		if (trace)
514 			printf("Image dimensions reversed.\n");
515 		return (1);
516 	}
517 
518 	if (fwidth < 2 || fheight < 2) {
519 		if (trace)
520 			printf("Target area too small\n");
521 		return (1);
522 	}
523 
524 	if (trace)
525 		printf("Image %ux%u -> %ux%u @%ux%u\n",
526 		    png->width, png->height, fwidth, fheight, ux1, uy1);
527 
528 	if ((flags & FL_PUTIMAGE_BORDER))
529 		gfx_fb_drawrect(ux1, uy1, ux2, uy2, 0);
530 
531 	data = malloc(fwidth * fheight * fb.fb_bpp);
532 	if (data == NULL) {
533 		if (trace)
534 			printf("Out of memory.\n");
535 		return (1);
536 	}
537 
538 	/*
539 	 * Build image for our framebuffer.
540 	 */
541 
542 	/* Helper to calculate the pixel index from the source png */
543 #define	GETPIXEL(xx, yy) (((yy) * png->width + (xx)) * png->bpp)
544 
545 	/*
546 	 * For each of the x and y directions, calculate the number of pixels
547 	 * in the source image that correspond to a single pixel in the target.
548 	 * Use fixed-point arithmetic with 16-bits for each of the integer and
549 	 * fractional parts.
550 	 */
551 	const uint32_t wcstep = ((png->width - 1) << 16) / (fwidth - 1);
552 	const uint32_t hcstep = ((png->height - 1) << 16) / (fheight - 1);
553 
554 	uint32_t hc = 0;
555 	for (y = 0; y < fheight; y++) {
556 		uint32_t hc2 = (hc >> 9) & 0x7f;
557 		uint32_t hc1 = 0x80 - hc2;
558 
559 		uint32_t offset_y = hc >> 16;
560 		uint32_t offset_y1 = offset_y + 1;
561 
562 		uint32_t wc = 0;
563 		for (x = 0; x < fwidth; x++) {
564 			uint32_t wc2 = (wc >> 9) & 0x7f;
565 			uint32_t wc1 = 0x80 - wc2;
566 
567 			uint32_t offset_x = wc >> 16;
568 			uint32_t offset_x1 = offset_x + 1;
569 
570 			/* Target pixel index */
571 			j = (y * fwidth + x) * fb.fb_bpp;
572 
573 			if (!scale) {
574 				i = GETPIXEL(x, y);
575 				r = png->image[i];
576 				g = png->image[i + 1];
577 				b = png->image[i + 2];
578 				a = png->image[i + 3];
579 			} else {
580 				uint8_t pixel[4];
581 
582 				uint32_t p00 = GETPIXEL(offset_x, offset_y);
583 				uint32_t p01 = GETPIXEL(offset_x, offset_y1);
584 				uint32_t p10 = GETPIXEL(offset_x1, offset_y);
585 				uint32_t p11 = GETPIXEL(offset_x1, offset_y1);
586 
587 				/*
588 				 * Given a 2x2 array of pixels in the source
589 				 * image, combine them to produce a single
590 				 * value for the pixel in the target image.
591 				 * Each column of pixels is combined using
592 				 * a weighted average where the top and bottom
593 				 * pixels contribute hc1 and hc2 respectively.
594 				 * The calculation for bottom pixel pB and
595 				 * top pixel pT is:
596 				 *   (pT * hc1 + pB * hc2) / (hc1 + hc2)
597 				 * Once the values are determined for the two
598 				 * columns of pixels, then the columns are
599 				 * averaged together in the same way but using
600 				 * wc1 and wc2 for the weightings.
601 				 *
602 				 * Since hc1 and hc2 are chosen so that
603 				 * hc1 + hc2 == 128 (and same for wc1 + wc2),
604 				 * the >> 14 below is a quick way to divide by
605 				 * (hc1 + hc2) * (wc1 + wc2)
606 				 */
607 				for (i = 0; i < 4; i++)
608 					pixel[i] = (
609 					    (png->image[p00 + i] * hc1 +
610 					    png->image[p01 + i] * hc2) * wc1 +
611 					    (png->image[p10 + i] * hc1 +
612 					    png->image[p11 + i] * hc2) * wc2)
613 					    >> 14;
614 
615 				r = pixel[0];
616 				g = pixel[1];
617 				b = pixel[2];
618 				a = pixel[3];
619 			}
620 
621 			color =
622 			    r >> (8 - fb.red_mask_size)
623 			    << fb.red_field_position |
624 			    g >> (8 - fb.green_mask_size)
625 			    << fb.green_field_position |
626 			    b >> (8 - fb.blue_mask_size)
627 			    << fb.blue_field_position;
628 
629 			switch (fb.fb_depth) {
630 			case 8: {
631 				uint32_t best, dist, k;
632 				int diff;
633 
634 				color = 0;
635 				best = 256 * 256 * 256;
636 				for (k = 0; k < 16; k++) {
637 					diff = r - cmap4_to_24.red[k];
638 					dist = diff * diff;
639 					diff = g - cmap4_to_24.green[k];
640 					dist += diff * diff;
641 					diff = b - cmap4_to_24.blue[k];
642 					dist += diff * diff;
643 
644 					if (dist < best) {
645 						color = k;
646 						best = dist;
647 						if (dist == 0)
648 							break;
649 					}
650 				}
651 				data[j] = solaris_color_to_pc_color[color];
652 				break;
653 			}
654 			case 15:
655 			case 16:
656 				*(uint16_t *)(data+j) = color;
657 				break;
658 			case 24:
659 				p = (uint8_t *)&color;
660 				data[j] = p[0];
661 				data[j+1] = p[1];
662 				data[j+2] = p[2];
663 				break;
664 			case 32:
665 				color |= a << 24;
666 				*(uint32_t *)(data+j) = color;
667 				break;
668 			}
669 			wc += wcstep;
670 		}
671 		hc += hcstep;
672 	}
673 
674 	gfx_fb_cons_display(uy1, ux1, fwidth, fheight, data);
675 	free(data);
676 	return (0);
677 }
678 
679 /*
680  * Implements alpha blending for RGBA data, could use pixels for arguments,
681  * but byte stream seems more generic.
682  * The generic alpha blending is:
683  * blend = alpha * fg + (1.0 - alpha) * bg.
684  * Since our alpha is not from range [0..1], we scale appropriately.
685  */
686 static uint8_t
687 alpha_blend(uint8_t fg, uint8_t bg, uint8_t alpha)
688 {
689 	uint16_t blend, h, l;
690 
691 	/* trivial corner cases */
692 	if (alpha == 0)
693 		return (bg);
694 	if (alpha == 0xFF)
695 		return (fg);
696 	blend = (alpha * fg + (0xFF - alpha) * bg);
697 	/* Division by 0xFF */
698 	h = blend >> 8;
699 	l = blend & 0xFF;
700 	if (h + l >= 0xFF)
701 		h++;
702 	return (h);
703 }
704 
705 /* Copy memory to framebuffer or to memory. */
706 static void
707 bitmap_cpy(uint8_t *dst, uint8_t *src, uint32_t len, int bpp)
708 {
709 	uint32_t i;
710 	uint8_t a;
711 
712 	switch (bpp) {
713 	case 4:
714 		for (i = 0; i < len; i += bpp) {
715 			a = src[i+3];
716 			dst[i] = alpha_blend(src[i], dst[i], a);
717 			dst[i+1] = alpha_blend(src[i+1], dst[i+1], a);
718 			dst[i+2] = alpha_blend(src[i+2], dst[i+2], a);
719 			dst[i+3] = a;
720 		}
721 		break;
722 	default:
723 		(void) memcpy(dst, src, len);
724 		break;
725 	}
726 }
727 
728 /*
729  * gfx_fb_cons_display implements direct draw on frame buffer memory.
730  * It is needed till we have way to send bitmaps to tem, tem already has
731  * function to send data down to framebuffer.
732  */
733 static void
734 gfx_fb_cons_display(uint32_t row, uint32_t col,
735     uint32_t width, uint32_t height, uint8_t *data)
736 {
737 	uint32_t size;		/* write size per scanline */
738 	uint8_t *fbp;		/* fb + calculated offset */
739 	int i;
740 
741 	/* make sure we will not write past FB */
742 	if (col >= fb.fb_width || row >= fb.fb_height ||
743 	    col + width > fb.fb_width || row + height > fb.fb_height)
744 		return;
745 
746 	size = width * fb.fb_bpp;
747 	fbp = fb.fb_addr + col * fb.fb_bpp + row * fb.fb_pitch;
748 
749 	/* write all scanlines in rectangle */
750 	for (i = 0; i < height; i++) {
751 		uint8_t *dest = fbp + i * fb.fb_pitch;
752 		uint8_t *src = data + i * size;
753 		bitmap_cpy(dest, src, size, fb.fb_bpp);
754 	}
755 }
756