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ubb-la/gui.c: use powers of two for zoom and integer arithmetic (WIP)

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This looks better and avoids the risk of math issues.
This commit is contained in:
Werner Almesberger 2013-01-30 20:35:30 -03:00
parent 94e099eebc
commit 1b0a2cff51
1 changed files with 90 additions and 21 deletions
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111
ubb-la/gui.c
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@ -30,7 +30,7 @@
#define CH_SKIP 16
#define CH_HEIGHT 8
#define MAX_ZOOM 8
#define MAX_ZOOM 3
static SDL_Surface *surf;
@ -77,34 +77,61 @@ static void change(int x, int ch)
}
static void level(int x, int ch, int v)
static void level(int x0, int x1, int ch, int v)
{
pixelColor(surf, x, ch_y(ch, v), LEVEL_RGBA);
if (x0 == x1)
pixelColor(surf, x0, ch_y(ch, v), LEVEL_RGBA);
else
hlineColor(surf, x0, x1, ch_y(ch, v), LEVEL_RGBA);
}
static void show_buffer(const uint8_t *buf, int skip, int nibbles,
static void show_buffer_zoom_in(const uint8_t *buf, int skip, int nibbles,
int x0, int x1)
{
double f = (nibbles-skip)/(x1-x0+1.0);
int f = (x1-x0)/(nibbles-skip);
int x, i, j;
int last[4] = { -1, -1, -1, -1};
uint8_t v, bit;
fprintf(stderr, "in: %d-%d (%d) Sa %d-%d (%d) pix %d f (%d)\n",
skip, nibbles, nibbles-skip, x0, x1, x1-x0, f, f*(nibbles-skip));
x = x0;
for (i = skip; i != nibbles; i++) {
v = (buf[i >> 1] >> 4*(~i & 1)) & 0xf;
for (j = 0; j != 4; j++) {
bit = (v >> j) & 1;
if (bit == last[j] || last[j] == -1) {
level(x, x+f-1, j, bit);
} else {
change(x, j);
level(x+1, x+f-1, j, bit);
}
last[j] = bit;
}
x += f;
}
}
static void show_buffer_zoom_out(const uint8_t *buf, int skip, int nibbles,
int x0, int x1)
{
int f = (nibbles-skip)/(x1-x0);
int x;
int i = skip-1, n, j;
int i = skip, n, j;
int changes[4], last[4] = { -1, -1, -1, -1}, next[4];
uint8_t v, bit;
for (x = x0; x != x1+1; x++) {
n = (x-x0)*f+skip;
if (i == n) {
for (j = 0; j != 4; j++)
level(x, j, last[j]);
continue;
}
fprintf(stderr, "out: %d-%d (%d) Sa %d-%d (%d) pix %d f (%d)\n",
skip, nibbles, nibbles-skip, x0, x1, x1-x0, f, f*(x1-x0));
for (x = x0; x != x1; x++) {
n = i+f;
for (j = 0; j != 4; j++) {
next[j] = last[j];
changes[j] = 0;
}
while (i != n) {
i++;
v = (buf[i >> 1] >> 4*(~i & 1)) & 0xf;
for (j = 0; j != 4; j++) {
bit = (v >> j) & 1;
@ -113,12 +140,13 @@ static void show_buffer(const uint8_t *buf, int skip, int nibbles,
next[j] = bit;
}
}
i++;
}
for (j = 0; j != 4; j++) {
if (changes[j] > 1)
bounce(x, j);
else if (!changes[j] || last[j] == -1)
level(x, j, next[j]);
level(x, x, j, next[j]);
else
change(x, j);
last[j] = next[j];
@ -127,6 +155,45 @@ static void show_buffer(const uint8_t *buf, int skip, int nibbles,
}
static void show_buffer(const uint8_t *buf, int skip, int nibbles,
int x0, int x1, int zoom, int pos)
{
int xm, w, p0, p1;
int d;
xm = (x0+x1) >> 1;
if (zoom < 0) {
w = (nibbles-skip) >> -zoom;
p0 = xm-(w >> 1);
p1 = xm+((w+1) >> 1);
if (p0 < x0) {
skip += (x0-p0) << -zoom;
p0 = x0;
}
if (p1 > x1) {
nibbles -= (p1-x1) << -zoom;
p1 = x1;
}
show_buffer_zoom_out(buf, skip, nibbles, p0, p1);
} else {
w = (nibbles-skip) << zoom;
p0 = xm-(w >> 1);
p1 = xm+((w+1) >> 1);
if (p0 < x0) {
d = ((x0-p0)+(1 << zoom)-1) >> zoom;
skip += d;
p0 += d << zoom;
}
if (p1 > x1) {
d = ((p1-x1)+(1 << zoom)-1) >> zoom;
nibbles -= d;
p1 -= d << zoom;
}
show_buffer_zoom_in(buf, skip, nibbles, p0, p1);
}
}
static void update(void)
{
SDL_UnlockSurface(surf);
@ -137,14 +204,16 @@ static void update(void)
void gui(const uint8_t *buf, int skip, int nibbles)
{
SDL_Event event;
int zoom = 0;
int m, w;
int pos = (skip+nibbles) >> 1;
int zoom; /* < 0: zoom out; 0: 1 pixel = 1 sample; > 1: zoom in */
int min_zoom = 0;
while (XRES-CH_XOFF < (nibbles-skip) >> -min_zoom)
min_zoom--;
zoom = min_zoom;
while (1) {
m = (nibbles-skip) >> 1;
w = (nibbles-skip) >> zoom;
clear();
show_buffer(buf, m-(w >> 1), m+(w >> 1), CH_XOFF, XRES-1);
show_buffer(buf, skip, nibbles, CH_XOFF, XRES, zoom, pos);
update();
do {
@ -157,7 +226,7 @@ void gui(const uint8_t *buf, int skip, int nibbles)
zoom++;
break;
case SDLK_DOWN:
if (zoom)
if (zoom > min_zoom)
zoom--;
break;
case SDLK_RETURN: