From 1abd53f564fa078d933473557ce8aae8d83b1aab Mon Sep 17 00:00:00 2001
From: Dan Prince <danprince@hey.com>
Date: Sun, 20 Mar 2022 09:04:36 +0100
Subject: [PATCH] automatically refresh after tileset loads

---
 README.md          |  4 +---
 example/example.ts |  7 ++-----
 src/index.ts       | 17 ++++++++++++-----
 3 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/README.md b/README.md
index dfff04b..2c4e916 100644
--- a/README.md
+++ b/README.md
@@ -18,9 +18,7 @@ term.color = "red";
 term.background = "#0000FF";
 term.put(0, 0, 0x10);
 term.write(10, 10, "Hello world");
-
-// Wait for the tileset to load before rendering
-term.tileset.onload = () => term.refresh();
+term.refresh();
 
 // Make the canvas visible
 document.body.append(term.canvas);
diff --git a/example/example.ts b/example/example.ts
index e6ab071..64a821f 100644
--- a/example/example.ts
+++ b/example/example.ts
@@ -24,10 +24,8 @@ onmousemove = e => {
   m = t.screenToGrid(e.clientX, e.clientY);
 }
 
-function start() {
-  drawBackground();
-  loop();
-}
+drawBackground();
+loop();
 
 function drawBackground() {
   t.layer = 1;
@@ -59,6 +57,5 @@ function loop() {
   t.refresh();
 }
 
-t.tileset.onload = start;
 t.canvas.style.background = "black";
 document.body.append(t.canvas);
diff --git a/src/index.ts b/src/index.ts
index 3eeac7e..1a9aeaa 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,4 +1,4 @@
-import defaultFontUrl from "./font.png";
+import defaultTilesetUrl from "./font.png";
 
 type TileSet = HTMLImageElement | HTMLCanvasElement;
 
@@ -112,12 +112,16 @@ export class Terminal {
   constructor(
     width: number,
     height: number,
-    url: string = defaultFontUrl,
+    url: string = defaultTilesetUrl,
     cellWidth = 6,
     cellHeight = 6,
   ) {
     let tileset = new Image();
     tileset.src = url;
+
+    // Draw anything that was buffered before the tileset loaded
+    tileset.addEventListener("load", () => this.refresh());
+
     let canvas = document.createElement("canvas");
     let ctx = canvas.getContext("2d")!;
     canvas.width = width * cellWidth;
@@ -246,7 +250,10 @@ export class Terminal {
    * Renders the terminal to the canvas.
    */
   refresh() {
-    let { canvas, ctx, tileset: font, width, cellWidth, cellHeight } = this;
+    // Can't render unless the tileset has loaded
+    if (this.tileset.width === 0) return;
+
+    let { canvas, ctx, tileset, width, cellWidth, cellHeight } = this;
     ctx.clearRect(0, 0, canvas.width, canvas.height);
 
     for (let layer of this.layers) {
@@ -261,8 +268,8 @@ export class Terminal {
           let bg = buffer[i++];
           let offsetX = buffer[i++];
           let offsetY = buffer[i++];
-          let img: HTMLImageElement | HTMLCanvasElement = font;
-          let cols = font.width / cellWidth;
+          let img: HTMLImageElement | HTMLCanvasElement = tileset;
+          let cols = tileset.width / cellWidth;
           let cw = cellWidth;
           let ch = cellHeight;
           let sx = (code % cols) * cw;