<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8" />
<title>chp3-2</title>
<meta name="description" content="" />
<meta name="author" content="Administrator" />
<script>
window.addEventListener("load", eventWindowLoaded, false);
function eventWindowLoaded() {
canvasApp();
}
function canvasApp() {
var message = "your text";
var fillOrStroke = "fill";
var fontSize = "50";
var fontFace = "serif";
var fontWeight = "normal";
var fontStyle = "normal";
var textBaseline = "middle";
var textAlign = "center";
var shadowX = 1;
var shadowY = 1;
var shadowBlur = 1;
var shadowColor = "#000000";
var textAltha = 1;
var theCanvas = document.getElementById("canvas");
var context = theCanvas.getContext("2d");
var formElement = document.getElementById("textBox");
formElement.addEventListener("keyup", textBoxChanged, false);
formElement = document.getElementById("fillOrStroke");
formElement.addEventListener("change", fillOrStrokeChanged, false);
formElement = document.getElementById("textSize");
formElement.addEventListener("change", textSizeChanged, false);
formElement = document.getElementById("textFont");
formElement.addEventListener("change", textFontChanged, false);
formElement = document.getElementById("fontWeight");
formElement.addEventListener("change", fontWeightChanged, false);
formElement = document.getElementById("fontStyle");
formElement.addEventListener("change", fontStyleChanged, false);
formElement = document.getElementById("textBaseline");
formElement.addEventListener("change", textBaselineChanged, false);
formElement = document.getElementById("textAlign");
formElement.addEventListener("change", textAlignChanged, false);
formElement = document.getElementById("shadowX");
formElement.addEventListener("change", shadowXChanged, false);
formElement = document.getElementById("shadowY");
formElement.addEventListener("change", shadowYChanged, false);
formElement = document.getElementById("shadowBlur");
formElement.addEventListener("change", shadowBlurChanged, false);
formElement = document.getElementById("textAlpha");
formElement.addEventListener("change", textAlphaChanged, false);
drawScreen();
function drawScreen() {
context.clearRect(0, 0, theCanvas.width, theCanvas.height);
context.fillStyle = "#ffffaa";
// context.fillRect(0, 0, theCanvas.width, theCanvas.height);
context.strokeStyle = "#000000";
// context.strokeRect(5, 5, theCanvas.width-10, theCanvas.height-10);
context.font = "50px serif";
context.textBaseline = textBaseline;
context.textAlign = textAlign;
context.globalAlpha = textAlpha;
context.shadowColor = shadowColor;
context.shadowOffsetX = shadowX;
context.shadowOffsetY = shadowY;
context.shadowBlur = shadowBlur;
var metrics = context.measureText(message);
var textWidth = metrics.width;
context.font = fontWeight + " " + fontStyle + " " + fontSize + "px " + fontFace;
//canvas中间点
var xPosition = (theCanvas.width - textWidth) / 2;
var yPosition = theCanvas.height / 2;
switch (fillOrStroke) {
case "fill":
context.fillStyle = "#ff0000";
context.fillText(message, xPosition, yPosition);
break;
case "stroke":
context.strokeStyle = "#FF0000";
context.strokeText(message, xPosition, yPosition);
break;
case "both":
context.fillStyle = "#ff0000";
context.fillText(message, xPosition, yPosition);
context.strokeStyle = "#000000";
context.strokeText(message, xPosition, yPosition);
break;
}
}
function textBoxChanged(e) {
var target = e.target;
message = target.value;
drawScreen();
}
function fillOrStrokeChanged(e) {
var target = e.target;
fillOrStroke = target.value;
drawScreen();
}
function textSizeChanged(e) {
var target = e.target;
fontSize = target.value;
drawScreen();
}
function textFontChanged(e) {
var target = e.target;
fontFace = target.value;
drawScreen();
}
function fontWeightChanged(e) {
var target = e.target;
fontWeight = target.value;
drawScreen();
}
function fontStyleChanged(e) {
var target = e.target;
fontStyle = target.value;
drawScreen();
}
function textAlignChanged(e) {
var target = e.target;
textAlign = target.value;
drawScreen();
}
function textBaselineChanged(e) {
var target = e.target;
textBaseline = target.value;
drawScreen();
}
function shadowXChanged(e) {
var target = e.target;
shadowX = target.value;
drawScreen();
}
function shadowYChanged(e) {
var target = e.target;
shadowY = target.value;
drawScreen();
}
function shadowBlurChanged(e) {
var target = e.target;
shadowBlur = target.value;
drawScreen();
}
function shadowColorChanged(e) {
var target = e.target;
shadowColor = target.value;
drawScreen();
}
function textAlphaChanged(e) {
var target = e.target;
textAlpha = target.value;
drawScreen();
}
}
</script>
</head>
<body>
<div style="position: absolute; top:50px; left: 50px; 500px; height:900px; border:3px solid #00ff90">
<canvas id="canvas" width="500"height="300">
</canvas>
<form>
Text:
<input id="textBox" placeholder="your text" />
<br>
Fill Or Stroke:
<select id="fillOrStroke">
<option value="fill">fill</option>
<option value="stroke">stroke</option>
<option value="both">both</option>
</select>
<br />
Font Style:
<select id="fontStyle">
<option value="normal">normal</option>
<option value="italic">italic</option>
<option value="oblique">oblique</option>
</select>
<br />
Font Weight:
<select id="fontWeight">
<option value="normal">normal</option>
<option value="bold">bold</option>
<option value="bolder">bolder</option>
<option value="lighter">lighter</option>
</select>
<br />
Text Font:
<select id="textFont">
<option value="serif">serif</option>
<option value="sans-serif">sans-serif</option>
<option value="cursive">cursive</option>
<option value="fantasy">fantasy</option>
<option value="monospace">monospace</option>
</select>
<br />
Text Size:
<input type="range" id="textSize" min="0" max="200" step="1" value="50" />
<br>
Text Baseline
<select id="textBaseline">
<option value="middle">middle</option>
<option value="top">top</option>
<option value="hanging">hanging</option>
<option value="alphabetic">alphabetic</option>
<option value="ideographic">ideographic</option>
<option value="bottom">bottom</option>
</select>
<br>
Text Align
<select id="textAlign">
<option value="center">center</option>
<option value="start">start</option>
<option value="end">end</option>
<option value="left">left</option>
<option value="right">right</option>
</select>
<br>
Alpha:<input type="range" id="textAlpha" min="0" max="1" step="0.1" value="1" />
<br>
Shadow X:<input type="range" id="shadowX" min="-100" max="100" step="1" value="1" />
<br>
Shadow Y:<input type="range" id="shadowY" min="-100" max="100" step="1" value="1" />
<br>
Shadow Blur:<input type="range" id="shadowBlur" min="1" max="100" step="1" value="1" />
<br>
Shadow Color:<input class="color" id="shadowColor" value="#000000" />
</form>
</div>
</body>
</html>