大家好我开发了一个使用javascript的车速表，我给了一个按钮和一个textfeild，其中如果我们在文本字段上给出一些值，速度表中的针将移动。现在我还创建了一个websocket，我想使用websocket服务器动态移动neddle。问题是websocket代码工作正常，但我无法使用Web套接字动态移动针。所以，任何人都可以帮我解决问题。这是速度计的代码。所以请帮助我使用websocket动态地在速度表上移动针。
<div class="container">
<h1>Hi there</h1>
<div>my friend</div>
</div>这是websocket的代码
(function () {
"use strict";
// this function is strict...
}());
var iCurrentSpeed = 20,
iTargetSpeed = 20,
bDecrement = null,
job = null;
function degToRad(angle) {
// Degrees to radians
return ((angle * Math.PI) / 180);
}
function radToDeg(angle) {
// Radians to degree
return ((angle * 180) / Math.PI);
}
function drawLine(options, line) {
// Draw a line using the line object passed in
options.ctx.beginPath();
// Set attributes of open
options.ctx.globalAlpha = line.alpha;
options.ctx.lineWidth = line.lineWidth;
options.ctx.fillStyle = line.fillStyle;
options.ctx.strokeStyle = line.fillStyle;
options.ctx.moveTo(line.from.X,
line.from.Y);
// Plot the line
options.ctx.lineTo(
line.to.X,
line.to.Y
);
options.ctx.stroke();
}
function createLine(fromX, fromY, toX, toY, fillStyle, lineWidth, alpha) {
// Create a line object using Javascript object notation
return {
from: {
X: fromX,
Y: fromY
},
to: {
X: toX,
Y: toY
},
fillStyle: fillStyle,
lineWidth: lineWidth,
alpha: alpha
};
}
function drawOuterMetallicArc(options) {
/* Draw the metallic border of the speedometer
* Outer grey area
*/
options.ctx.beginPath();
// Nice shade of grey
options.ctx.fillStyle = "rgb(127,127,127)";
// Draw the outer circle
options.ctx.arc(options.center.X,
options.center.Y,
options.radius,
0,
Math.PI,
true);
// Fill the last object
options.ctx.fill();
}
function drawInnerMetallicArc(options) {
/* Draw the metallic border of the speedometer
* Inner white area
*/
options.ctx.beginPath();
// White
options.ctx.fillStyle = "rgb(255,255,255)";
// Outer circle (subtle edge in the grey)
options.ctx.arc(options.center.X,
options.center.Y, (options.radius / 100) * 90,
0,
Math.PI,
true);
options.ctx.fill();
}
function drawMetallicArc(options) {
/* Draw the metallic border of the speedometer
* by drawing two semi-circles, one over lapping
* the other with a bot of alpha transparency
*/
drawOuterMetallicArc(options);
drawInnerMetallicArc(options);
}
function drawBackground(options) {
/* Black background with alphs transparency to
* blend the edges of the metallic edge and
* black background
*/
var i = 0;
options.ctx.globalAlpha = 0.2;
options.ctx.fillStyle = "rgb(0,0,0)";
// Draw semi-transparent circles
for (i = 170; i < 180; i++) {
options.ctx.beginPath();
options.ctx.arc(options.center.X,
options.center.Y,
i,
0,
Math.PI,
true);
options.ctx.fill();
}
}
function applyDefaultContextSettings(options) {
/* Helper function to revert to gauges
* default settings
*/
options.ctx.lineWidth = 2;
options.ctx.globalAlpha = 0.5;
options.ctx.strokeStyle = "rgb(255, 255, 255)";
options.ctx.fillStyle = 'rgb(255,255,255)';
}
function drawSmallTickMarks(options) {
/* The small tick marks against the coloured
* arc drawn every 5 mph from 10 degrees to
* 170 degrees.
*/
var tickvalue = options.levelRadius - 8,
iTick = 0,
gaugeOptions = options.gaugeOptions,
iTickRad = 0,
onArchX,
onArchY,
innerTickX,
innerTickY,
fromX,
fromY,
line,
toX,
toY;
applyDefaultContextSettings(options);
}
function drawLargeTickMarks(options) {
/* The large tick marks against the coloured
* arc drawn every 10 mph from 10 degrees to
* 170 degrees.
*/
var tickvalue = options.levelRadius - 8,
iTick = 0,
gaugeOptions = options.gaugeOptions,
iTickRad = 0,
innerTickY,
innerTickX,
onArchX,
onArchY,
fromX,
fromY,
toX,
toY,
line;
applyDefaultContextSettings(options);
tickvalue = options.levelRadius - 2;
// 10 units (major ticks)
for (iTick = 50; iTick < 145; iTick += 20) {
iTickRad = degToRad(iTick);
/* Calculate the X and Y of both ends of the
* line I need to draw at angle represented at Tick.
* The aim is to draw the a line starting on the
* coloured arc and continueing towards the outer edge
* in the direction from the center of the gauge.
*/
onArchX = gaugeOptions.radius - (Math.cos(iTickRad) * tickvalue);
onArchY = gaugeOptions.radius - (Math.sin(iTickRad) * tickvalue);
innerTickX = gaugeOptions.radius - (Math.cos(iTickRad) * gaugeOptions.radius);
innerTickY = gaugeOptions.radius - (Math.sin(iTickRad) * gaugeOptions.radius);
fromX = (options.center.X - gaugeOptions.radius) + onArchX;
fromY = (gaugeOptions.center.Y - gaugeOptions.radius) + onArchY;
toX = (options.center.X - gaugeOptions.radius) + innerTickX;
toY = (gaugeOptions.center.Y - gaugeOptions.radius) + innerTickY;
// Create a line expressed in JSON
line = createLine(fromX, fromY, toX, toY, "rgb(127,127,127)", 3, 0.6);
// Draw the line
drawLine(options, line);
}
}
function drawTicks(options) {
/* Two tick in the coloured arc!
* Small ticks every 5
* Large ticks every 10
*/
drawSmallTickMarks(options);
drawLargeTickMarks(options);
}
function drawTextMarkers(options) {
/* The text labels marks above the coloured
* arc drawn every 10 mph from 10 degrees to
* 170 degrees.
*/
var innerTickX = 0,
innerTickY = 0,
iTick = 0,
gaugeOptions = options.gaugeOptions,
iTickToPrint = 80;
applyDefaultContextSettings(options);
// Font styling
options.ctx.font = 'italic 10px sans-serif';
options.ctx.textBaseline = 'top';
options.ctx.beginPath();
// Tick every 20 (small ticks)
for (iTick = 50; iTick < 145; iTick += 20) {
innerTickX = gaugeOptions.radius - (Math.cos(degToRad(iTick)) * gaugeOptions.radius);
innerTickY = gaugeOptions.radius - (Math.sin(degToRad(iTick)) * gaugeOptions.radius);
// Some cludging to center the values (TODO: Improve)
if (iTick <= 10) {
options.ctx.fillText(iTickToPrint, (options.center.X - gaugeOptions.radius - 12) + innerTickX, (gaugeOptions.center.Y - gaugeOptions.radius - 12) + innerTickY + 5);
} else if (iTick < 50) {
options.ctx.fillText(iTickToPrint, (options.center.X - gaugeOptions.radius - 12) + innerTickX - 5, (gaugeOptions.center.Y - gaugeOptions.radius - 12) + innerTickY + 5);
} else if (iTick < 90) {
options.ctx.fillText(iTickToPrint, (options.center.X - gaugeOptions.radius - 12) + innerTickX, (gaugeOptions.center.Y - gaugeOptions.radius - 12) + innerTickY);
} else if (iTick === 90) {
options.ctx.fillText(iTickToPrint, (options.center.X - gaugeOptions.radius - 12) + innerTickX + 4, (gaugeOptions.center.Y - gaugeOptions.radius - 12) + innerTickY);
} else if (iTick < 145) {
options.ctx.fillText(iTickToPrint, (options.center.X - gaugeOptions.radius - 12) + innerTickX + 10, (gaugeOptions.center.Y - gaugeOptions.radius - 12) + innerTickY);
} else {
options.ctx.fillText(iTickToPrint, (options.center.X - gaugeOptions.radius - 12) + innerTickX + 15, (gaugeOptions.center.Y - gaugeOptions.radius - 12) + innerTickY + 5);
}
// MPH increase by 10 every 20 degrees
iTickToPrint += Math.round(2160 / 9);
}
options.ctx.stroke();
}
function drawSpeedometerPart(options, alphaValue, strokeStyle, startPos) {
/* Draw part of the arc that represents
* the colour speedometer arc
*/
options.ctx.beginPath();
options.ctx.globalAlpha = alphaValue;
options.ctx.lineWidth = 5;
options.ctx.strokeStyle = strokeStyle;
options.ctx.arc(options.center.X,
options.center.Y,
options.levelRadius,
Math.PI + (Math.PI / 360 * startPos),
0 - (Math.PI / 360 * 10),
false);
options.ctx.stroke();
}
function drawSpeedometerColourArc(options) {
/* Draws the colour arc. Three different colours
* used here; thus, same arc drawn 3 times with
* different colours.
* TODO: Gradient possible?
*/
var startOfGreen = 100,
endOfGreen = 180,
endOfOrange = 220,
endofRed = 260;
drawSpeedometerPart(options, 1.0, "rgb(82, 240, 55)", startOfGreen);
drawSpeedometerPart(options, 0.9, "rgb(198, 111, 0)", endOfGreen);
drawSpeedometerPart(options, 0.9, "rgb(255, 0, 0)", endOfOrange);
drawSpeedometerPart(options, 1.0, "rgb(0,0, 0,2)", endofRed);
}
function drawNeedleDial(options, alphaValue, strokeStyle, fillStyle) {
/* Draws the metallic dial that covers the base of the
* needle.
*/
var i = 0;
options.ctx.globalAlpha = alphaValue;
options.ctx.lineWidth = 3;
options.ctx.strokeStyle = strokeStyle;
options.ctx.fillStyle = fillStyle;
// Draw several transparent circles with alpha
for (i = 0; i < 30; i++) {
options.ctx.beginPath();
options.ctx.arc(options.center.X,
options.center.Y,
i,
0,
Math.PI,
true);
options.ctx.fill();
options.ctx.stroke();
}
}
function convertSpeedToAngle(options) {
/* Helper function to convert a speed to the
* equivelant angle.
*/
var iSpeed = (options.speed / 10),
iSpeedAsAngle = ((iSpeed * 20) + 10) % 180;
// Ensure the angle is within range
if (iSpeedAsAngle > 180) {
iSpeedAsAngle = iSpeedAsAngle - 180;
} else if (iSpeedAsAngle < 0) {
iSpeedAsAngle = iSpeedAsAngle + 180;
}
return iSpeedAsAngle;
}
function drawNeedle(options) {
/* Draw the needle in a nice read colour at the
* angle that represents the options.speed value.
*/
var iSpeedAsAngle = convertSpeedToAngle(options),
iSpeedAsAngleRad = degToRad(iSpeedAsAngle),
gaugeOptions = options.gaugeOptions,
innerTickX = gaugeOptions.radius - (Math.cos(iSpeedAsAngleRad) * 20),
innerTickY = gaugeOptions.radius - (Math.sin(iSpeedAsAngleRad) * 20),
fromX = (options.center.X - gaugeOptions.radius) + innerTickX,
fromY = (gaugeOptions.center.Y - gaugeOptions.radius) + innerTickY,
endNeedleX = gaugeOptions.radius - (Math.cos(iSpeedAsAngleRad) * gaugeOptions.radius),
endNeedleY = gaugeOptions.radius - (Math.sin(iSpeedAsAngleRad) * gaugeOptions.radius),
toX = (options.center.X - gaugeOptions.radius) + endNeedleX,
toY = (gaugeOptions.center.Y - gaugeOptions.radius) + endNeedleY,
line = createLine(fromX, fromY, toX, toY, "rgb(255,0,0)", 5, 0.6);
drawLine(options, line);
// Two circle to draw the dial at the base (give its a nice effect?)
drawNeedleDial(options, 0.6, "rgb(127, F27, 127)", "rgb(255,255,255)");
drawNeedleDial(options, 0.2, "rgb(127, 127, 127)", "rgb(127,127,127)");
}
function buildOptionsAsJSON(canvas, iSpeed) {
/* Setting for the speedometer
* Alter these to modify its look and feel
*/
var centerX = 210,
centerY = 210,
radius = 140,
outerRadius = 200;
// Create a speedometer object using Javascript object notation
return {
ctx: canvas.getContext('2d'),
speed: iSpeed,
center: {
X: centerX,
Y: centerY
},
levelRadius: radius - 10,
gaugeOptions: {
center: {
X: centerX,
Y: centerY
},
radius: radius
},
radius: outerRadius
};
}
function clearCanvas(options) {
options.ctx.clearRect(0, 0, 800, 600);
applyDefaultContextSettings(options);
}
function draw() {
/* Main entry point for drawing the speedometer
* If canvas is not support alert the user.
*/
console.log('Target: ' + iTargetSpeed);
console.log('Current: ' + iCurrentSpeed);
var canvas = document.getElementById('tutorial'),
options = null;
// Canvas good?
if (canvas !== null && canvas.getContext) {
options = buildOptionsAsJSON(canvas, iCurrentSpeed);
// Clear canvas
clearCanvas(options);
// Draw the metallic styled edge
drawMetallicArc(options);
// Draw thw background
drawBackground(options);
// Draw tick marks
drawTicks(options);
// Draw labels on markers
drawTextMarkers(options);
// Draw speeometer colour arc
drawSpeedometerColourArc(options);
// Draw the needle and base
drawNeedle(options);
} else {
alert("Canvas not supported by your browser!");
}
if (iTargetSpeed == iCurrentSpeed) {
clearTimeout(job);
return;
} else if (iTargetSpeed < iCurrentSpeed) {
bDecrement = true;
} else if (iTargetSpeed > iCurrentSpeed) {
bDecrement = false;
}
if (bDecrement) {
if (iCurrentSpeed - 10 < iTargetSpeed)
iCurrentSpeed = iCurrentSpeed - 1;
else
iCurrentSpeed = iCurrentSpeed - 5;
} else {
if (iCurrentSpeed + 10 > iTargetSpeed)
iCurrentSpeed = iCurrentSpeed + 1;
else
iCurrentSpeed = iCurrentSpeed + 5;
}
job = setTimeout("draw()", 5);
}
function drawWithInputValue() {
var txtSpeed = document.getElementById('txtSpeed');
if (txtSpeed !== null) {
iTargetSpeed = txtSpeed.value;
// Sanity checks
if (isNaN(iTargetSpeed)) {
iTargetSpeed = 20;
} else if (iTargetSpeed < 20) {
iTargetSpeed = 20;
} else if (iTargetSpeed > 60) {
iTargetSpeed = 60;
}
job = setTimeout("draw()", 5);
}
}
答案 0 :(得分：0)
}
select A into B from teste where A='1';
function writeResponse(text){
messages.innerHTML += "<br/>" + text;
}
</script>
这是我在网络套接字代码末尾错过的代码。
答案 1 :(得分：0)
所以我能说的最好，你需要工作的唯一方法是在传递websocket消息时以某种方式触发画布绘制。我对你提供的代码做了一些修改，所以它完整，你有一些东西缺失，如画布和正确的文本输入id，并创建了一个jsfiddle。 Essentiall你需要改变的是onmessage eventhandler和drawWithInputValue函数，类似于：
webSocket.onmessage = function(event){
if(event.data.type == "speed"){
drawWithInputValue(event.data.value);
}
writeResponse(event.data);
};
function drawWithInputValue(txtSpeed) {
if (txtSpeed !== null) {
iTargetSpeed = txtSpeed.value;
// Sanity checks
if (isNaN(iTargetSpeed)) {
iTargetSpeed = 20;
} else if (iTargetSpeed < 20) {
iTargetSpeed = 20;
} else if (iTargetSpeed > 60) {
iTargetSpeed = 60;
}
job = setTimeout("draw()", 5);
}
}
function drawWithInputValueLocal(){
var txtSpeed = document.getElementById('messageinput');
drawWithInputValue(txtSpeed)
}
现在在你的绘图按钮的onclick处理程序中，只需将其更改为：
<button type="button" onclick="drawWithInputValueLocal();" >Draw</button>
现在，当您的websocket服务器以如下格式发送消息时：
{
type : 'speed',
value : 30
}
onmessage事件处理程序将检查该消息类型，然后将值发送到drawInputValue函数。
最后一点，我不完全确定为什么你的代码顶部有这个闭包似乎什么都不做：
(function () {
"use strict";
// this function is strict...
}());
如果您想使代码模块化，您需要将所有变量和函数放在其中，然后将其导出以供页面使用。