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feat(text-canvas): add bresenham line & circle fns, force int coords
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@postspectacular
postspectacular committed Feb 14, 2020
1 parent d5bdcc8 commit 0587a66
Showing 1 changed file with 147 additions and 12 deletions.
159 changes: 147 additions & 12 deletions packages/text-canvas/src/canvas.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -48,13 +48,25 @@ export const clear = (canvas: Canvas, char = " ") => {
}
};

const intersectRect = (a: ClipRect, b: ClipRect): ClipRect => {
const x1 = Math.max(a.x1, b.x1);
const y1 = Math.max(a.y1, b.y1);
const x2 = Math.min(a.x2, b.x2);
const y2 = Math.min(a.y2, b.y2);
return { x1, y1, x2, y2, w: Math.max(x2 - x1, 0), h: Math.max(y2 - y1, 0) };
};

export const beginClip = (
canvas: Canvas,
x: number,
y: number,
w: number,
h: number
) => {
x |= 0;
y |= 0;
w |= 0;
h |= 0;
const { width, height } = canvas;
const x2 = clamp(x + w, 0, width);
const y2 = clamp(y + h, 0, height);
Expand Down Expand Up @@ -84,12 +96,22 @@ export const endStyle = (canvas: Canvas) => {
}
};

export const setAt = (canvas: Canvas, x: number, y: number, char: string) => {
x |= 0;
y |= 0;
const { x1, y1, x2, y2 } = peek(canvas.clipRects);
if (x < x1 || y < y1 || x >= x2 || y >= y2) return;
canvas.buf[x + y * canvas.width] = char;
};

export const textLine = (
canvas: Canvas,
x: number,
y: number,
line: string
) => {
x |= 0;
y |= 0;
const { x1, y1, x2, y2 } = peek(canvas.clipRects);
if (y < y1 || y >= y2 || x >= x2) return;
let i = 0;
Expand All @@ -107,13 +129,16 @@ export const textLine = (
}
};

export const wrappedText = (
export const textColumn = (
canvas: Canvas,
x: number,
y: number,
width: number,
txt: string
) => {
x |= 0;
y |= 0;
width |= 0;
const height = canvas.height;
for (let line of txt.split("\n")) {
for (let words of wordWrap(width, line.split(" "))) {
Expand All @@ -133,6 +158,10 @@ export const fillRect = (
h: number,
char: string
) => {
x |= 0;
y |= 0;
w |= 0;
h |= 0;
const { x1, y1, x2, y2 } = peek(canvas.clipRects);
if (x < x1) {
w += x - x1;
Expand All @@ -159,6 +188,10 @@ export const strokeRect = (
w: number,
h: number
) => {
x |= 0;
y |= 0;
w |= 0;
h |= 0;
if (w < 2 || h < 2) return;
const style = peek(canvas.styles);
hline(canvas, x, y, w, style.tl, style.tr);
Expand All @@ -176,10 +209,13 @@ export const hline = (
e?: string,
m?: string
) => {
x |= 0;
y |= 0;
len |= 0;
const { x1, y1, x2, y2 } = peek(canvas.clipRects);
const { buf, width } = canvas;
if (len < 1 || y < y1 || y >= y2 || x >= x2) return;
_line(buf, x, y, 1, width, x1, x2, len, peek(canvas.styles).hl, s, e, m);
_hvline(buf, x, y, 1, width, x1, x2, len, peek(canvas.styles).hl, s, e, m);
};

export const vline = (
Expand All @@ -191,13 +227,16 @@ export const vline = (
e?: string,
m?: string
) => {
x |= 0;
y |= 0;
len |= 0;
const { x1, x2, y1, y2 } = peek(canvas.clipRects);
const { buf, width } = canvas;
if (len < 1 || x < x1 || x >= x2 || y >= y2) return;
_line(buf, y, x, width, 1, y1, y2, len, peek(canvas.styles).vl, s, e, m);
_hvline(buf, y, x, width, 1, y1, y2, len, peek(canvas.styles).vl, s, e, m);
};

const _line = (
const _hvline = (
buf: string[],
a: number,
b: number,
Expand Down Expand Up @@ -233,12 +272,108 @@ const _line = (
}
};

const intersectRect = (a: ClipRect, b: ClipRect): ClipRect => {
const x1 = Math.max(a.x1, b.x1);
const y1 = Math.max(a.y1, b.y1);
const x2 = Math.min(a.x2, b.x2);
const y2 = Math.min(a.y2, b.y2);
const w = Math.max(x2 - x1, 0);
const h = Math.max(y2 - y1, 0);
return { x1, y1, x2, y2, w, h };
export const line = (
canvas: Canvas,
ax: number,
ay: number,
bx: number,
by: number,
char?: string
) => {
ax |= 0;
ay |= 0;
bx |= 0;
by |= 0;
const dx = Math.abs(bx - ax);
const dy = -Math.abs(by - ay);
const w = canvas.width;
const { x1, y1, x2, y2 } = peek(canvas.clipRects);

let sx = ax < bx ? 1 : -1;
let sy = ay < by ? 1 : -1;
let err = dx + dy;

char = char !== undefined ? char : peek(canvas.styles).dot;

while (true) {
if (ax >= x1 && ay >= y1 && ax < x2 && ay < y2) {
canvas.buf[ax + ay * w] = char;
}
if (ax === bx && ay === by) return;
let t = err << 1;
if (t < dx) {
err += dx;
ay += sy;
}
if (t > dy) {
err += dy;
ax += sx;
}
}
};

export const circle = (
canvas: Canvas,
cx: number,
cy: number,
r: number,
char?: string,
fill = false
) => {
if (r < 1) return;
cx |= 0;
cy |= 0;
r |= 0;
char = char !== undefined ? char : peek(canvas.styles).dot;

let x = 0;
let y = r;
let ymax = r * r;
let sum = ymax + r;
let dx2 = 1;
let dy2 = 2 * r - 1;

const { buf, width } = canvas;
const { x1, y1, x2, y2 } = peek(canvas.clipRects);

const $ = (ox: number, oy: number) =>
ox >= x1 &&
oy >= y1 &&
ox < x2 &&
oy < y2 &&
(buf[ox + oy * width] = char!);

while (x <= y) {
if (fill) {
hline(canvas, cx - y, cy + x, y << 1, char, char, char);
x && hline(canvas, cx - y, cy - x, y << 1, char, char, char);
} else {
$(cx - y, cy + x);
y && $(cx + y, cy + x);
if (x) {
$(cx - y, cy - x);
y && $(cx + y, cy - x);
}
if (x !== y) {
$(cx - x, cy - y);
x && $(cx + x, cy - y);
if (y) {
$(cx - x, cy + y);
x && $(cx + x, cy + y);
}
}
}
sum -= dx2;
if (sum <= ymax) {
if (fill && x !== y) {
hline(canvas, cx - x, cy - y, x << 1, char, char, char);
y && hline(canvas, cx - x, cy + y, x << 1, char, char, char);
}
y--;
ymax -= dy2;
dy2 -= 2;
}
x++;
dx2 += 2;
}
};

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