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Draw continuous lines 

So that the application is actually usable in shitty terminals.
This commit is contained in:
Přemysl Eric Janouch 2014-11-29 23:58:41 +01:00
parent a47ed4fe84
commit 08a2d53eb4
1 changed files with 60 additions and 2 deletions
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62
autistdraw.c
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@ -497,6 +497,14 @@ make_place_for_point (app_context_t *app, int x, int y)
static void
draw_point (app_context_t *app, int x, int y, uint8_t color)
{
// We don't actually draw anything immediately in client mode,
// instead we wait for confirmation from the server
if (app->mode == NETWORK_MODE_CLIENT)
{
send_draw_point_request (app, x, y, color);
return;
}
make_place_for_point (app, x, y);
BITMAP_PIXEL (app, x - app->bitmap_x, y - app->bitmap_y) = color;
@ -516,6 +524,50 @@ draw_point (app_context_t *app, int x, int y, uint8_t color)
send_draw_point_response (iter, x, y, color);
}
static void
draw_line (app_context_t *app, int x0, int x1, int y0, int y1, uint8_t color)
{
// Integer version of Bresenham's line drawing algorithm,
// loosely based on code from libcaca because screw math
int dx = abs (x1 - x0);
int dy = abs (y1 - y0);
bool steep = dx < dy;
if (steep)
{
// Flip the coordinate system on input
int tmp;
tmp = x0; x0 = y0; y0 = tmp;
tmp = x1; x1 = y1; y1 = tmp;
tmp = dx; dx = dy; dy = tmp;
}
int step_x = x0 > x1 ? -1 : 1;
int step_y = y0 > y1 ? -1 : 1;
int dpr = dy * 2;
int delta = dpr - dx;
int dpru = delta - dx;
while (dx-- >= 0)
{
// Unflip the coordinate system on output
if (steep)
draw_point (app, y0, x0, color);
else
draw_point (app, x0, y0, color);
x0 += step_x;
if (delta > 0)
{
y0 += step_y;
delta += dpru;
}
else
delta += dpr;
}
}
// --- Exports -----------------------------------------------------------------
static bool
@ -854,10 +906,16 @@ on_mouse (app_context_t *app, termo_key_t *key)
if (screen_y >= TOP_BAR_CUTOFF)
{
if (app->mode == NETWORK_MODE_CLIENT)
send_draw_point_request (app, canvas_x, canvas_y, *color);
if (event == TERMO_MOUSE_DRAG)
draw_line (app,
app->move_saved_x, canvas_x,
app->move_saved_y, canvas_y,
*color);
else
draw_point (app, canvas_x, canvas_y, *color);
app->move_saved_x = canvas_x;
app->move_saved_y = canvas_y;
}
else if (screen_y > 0 && event != TERMO_MOUSE_DRAG)
{