feat(text-canvas): major update/rewrite, format support

- use Uint32Array as backing buffer
- add support for arbitrary format IDs (highest 16bit)
- add configurable string formatting
- add ANSI & HTML format presets
- add color & format constants
- re-org source files

packages/text-canvas/src/ansi.ts

@@ -0,0 +1,26 @@
+import { memoize1 } from "@thi.ng/memoize";
+import { StringFormat } from "./api";
+
+const ANSI_RESET = `\u001B[0m`;
+
+const ANSI_FLAGS = ["", "1", "2", "1;2", "4", "1;4", "2;4", "1;2;4"];
+
+/**
+ * String format preset, translating canvas format info to ANSI 4bit
+ * control sequences.
+ */
+export const FMT_ANSI16: StringFormat = {
+    start: memoize1((x: number) => {
+        let res = [];
+        let y = x & 0xf;
+        y && res.push(29 + ((x >> 4) & 1) * 60 + y);
+        y = (x >> 5) & 0xf;
+        y && res.push(39 + ((x >> 9) & 1) * 60 + y);
+        y = x >> 10;
+        y && res.push(ANSI_FLAGS[y]);
+        return "\u001b[" + res.join(";") + "m";
+    }),
+    end: ANSI_RESET,
+    prefix: ANSI_RESET,
+    suffix: "\n"
+};

packages/text-canvas/src/api.ts

@@ -1,6 +1,100 @@
-import { IObjectOf } from "@thi.ng/api";
+import { Fn, IObjectOf } from "@thi.ng/api";
 
-export const ENDINGS = "▶◀▲▼•●";
+export interface ClipRect {
+    x1: number;
+    y1: number;
+    x2: number;
+    y2: number;
+    w: number;
+    h: number;
+}
+
+export interface StringFormat {
+    /**
+     * Function translating canvas character format codes to the actual
+     * output format. This function will only be called when needed,
+     * i.e. when a character's format is different than that of the
+     * previous.
+     */
+    start: Fn<number, string>;
+    /**
+     * Format end string.
+     */
+    end: string;
+    /**
+     * Prefix for entire canvas result string
+     */
+    prefix: string;
+    /**
+     * Suffix for entire canvas result string
+     */
+    suffix: string;
+}
+
+export interface HtmlFormatOpts {
+    /**
+     * Array of 16 color strings, in this order: black, red, green,
+     * yellow, blue, magenta, cyan, white, then repeated as bright
+     * versions.
+     */
+    colors: string[];
+    /**
+     * HTML attrib name.
+     */
+    attrib: string;
+    /**
+     * Delimiter between individual formatting terms, e.g. `;` for CSS
+     * rules or ` ` for CSS class names.
+     */
+    delim: string;
+    /**
+     * Prefix string for foreground colors
+     */
+    fg: string;
+    /**
+     * Prefix string for background colors
+     */
+    bg: string;
+    bold: string;
+    dim: string;
+    underline: string;
+}
+
+// bits 0-3: fg
+// bit 3: bright fg
+// bits 4-7: bg
+// bit 8: bright bg
+// bit 9: bold
+// bit 10: dim
+// bit 11: underline
+
+export const NONE = 0;
+export const FG_BLACK = 1;
+export const FG_RED = 2;
+export const FG_GREEN = 3;
+export const FG_YELLOW = 4;
+export const FG_BLUE = 5;
+export const FG_MAGENTA = 6;
+export const FG_CYAN = 7;
+export const FG_WHITE = 8;
+
+export const BG_BLACK = 1 << 5;
+export const BG_RED = 2 << 5;
+export const BG_GREEN = 3 << 5;
+export const BG_YELLOW = 4 << 5;
+export const BG_BLUE = 5 << 5;
+export const BG_MAGENTA = 6 << 5;
+export const BG_CYAN = 7 << 5;
+export const BG_WHITE = 8 << 5;
+
+export const FG_BRIGHT = 1 << 4;
+export const BG_BRIGHT = 1 << 9;
+
+export const BOLD = 1 << 10;
+export const DIM = 1 << 11;
+export const UNDERLINE = 1 << 12;
+
+export const ENDINGS = "()[]{}<>◀▶▲▼•●";
 
 export interface StrokeStyle {
     hl: string;