1#include "draw.h"
 2
 3static void draw_bitmap(uint32_t* dst, int w, int h, uint8_t* bmp,
 4                        int bw, int bh, int x, int y, uint32_t fg);
 5static void blend(uint32_t* dst, int w, int h, int x, int y, uint8_t alpha,
 6                  uint32_t fg);
 7
 8/* draw bitmap of properties (look: vvvv) to screen */
 9static void draw_bitmap(uint32_t* dst, int w, int h, uint8_t* bmp,
10		int bw, int bh, int x, int y, uint32_t fg)
11{
12	for (int by = 0; by < bh; by++) {
13		for (int bx = 0; bx < bw; bx++) {
14			uint8_t a = bmp[by * bw + bx];
15			blend(dst, w, h, x + bx, y + by, a, fg);
16		}
17	}
18}
19
20/* blend a pixel using alpha compositong */
21static void blend(uint32_t* dst, int w, int h, int x, int y, uint8_t alpha,
22                  uint32_t fg)
23{
24	uint8_t* px;
25	uint8_t fg_r;
26	uint8_t fg_g;
27	uint8_t fg_b;
28
29	if (x < 0 || x >= w || y < 0 || y >= h || alpha == 0)
30		return; /* transparent/oob */
31
32	/* ptr to px at (x, y) */
33	px = (uint8_t*)&dst[y * w + x];
34
35	/* unpack fg colour*/
36	fg_r = (uint8_t)(fg & 0xff);
37	fg_g = (uint8_t)((fg >> 8) & 0xff);
38	fg_b = (uint8_t)((fg >> 16) & 0xff);
39
40	/* alpha blend each channel */
41	px[0] = (uint8_t)((fg_r * alpha + px[0] * (255 - alpha)) / 255);
42	px[1] = (uint8_t)((fg_g * alpha + px[1] * (255 - alpha)) / 255);
43	px[2] = (uint8_t)((fg_b * alpha + px[2] * (255 - alpha)) / 255);
44
45	px[3] = 255;
46}
47
48void draw_clear(uint32_t* dst, int w, int h, uint32_t col)
49{
50	for (int i = 0; i < w*h; i++)
51		dst[i] = col;
52}
53
54void draw_rune(uint32_t* dst, int w, int h, int cl, int rw, int cw, int ch,
55               uint32_t bg)
56{
57	int x0 = cl * cw; /* x origin of cell */
58	int y0 = rw * ch; /* y origin of cell */
59	int x;
60	int y;
61
62	/* iterate through columns */
63	for (y = y0; y < y0+ch && y < h; y++) {
64		if (y < 0)
65			continue;
66
67
68		/* through rows */
69		for (x = x0; x < x0+cw && x < w; x++) {
70			if (x < 0)
71				continue;
72			dst[y * w + x] = bg;
73		}
74	}
75}
76
77void draw_codepoint(Fontface* f, uint32_t* dst, int w, int h, int x,
78		int baseline, uint32_t cp, uint32_t fg)
79{
80	if (!f || !dst)
81		return;
82
83	if (!f->bdf || cp >= BDF_GLYPHS_MAX)
84		return;
85
86	BdfGlyph* g = &f->bdf[cp];
87	if (!g->valid)
88		return;
89
90	draw_bitmap(
91		dst, w, h, g->bmp, g->w, g->h, x + g->xoff,
92		baseline - g->yoff - g->h, fg
93	);
94}
95