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HTML5 Canvas 2D Rendering Engine
Get cax through npm or cdn:
npm i cax
Usage:
import cax from 'cax'
const stage = new cax.Stage(200, 200, 'body')
cax.loadImgs({
imgs: ['./wepay-diy.jpg'],
complete: (imgs) => {
const img = imgs[0]
const bitmap = new cax.Bitmap(img)
bitmap.x = stage.width / 2
bitmap.y = stage.height / 2
bitmap.rotation = -10
bitmap.originX = img.width / 2
bitmap.originY = img.height / 2
bitmap.filter('blur(10px)')
stage.add(bitmap)
stage.update()
}
})
You will see the following effect:
For grouping, group can also nested group, and the parent container's properties will be superimposed on child properties, such as:
const group = new cax.Group()
const rect = new cax.Rect(100, 100, {
fillStyle: 'black'
})
group.add(rect)
stage.add(group)
stage.update()
Group has commonly used add and remove methods to add and delete elements. The first add will be drawn first, and all subsequent add will be covered above the top add.
add child to group
groupObj.add(child)
remove child from group
groupObj.remove(child)
remove all the children from group
groupObj.empty()
replace child by another obj
groupObj.replace (current, pre)
Stage is the largest top container inherited from Group, so have all the methods and props of Group.
Any element can't be seen on the stage. You must execute the update method.
stage.update()
Any element property is modified. Please perform stage.update() to update the stage, or put it in the timer.
cax.tick(stage.update.bind(stage))
When the height of the canvas and the pixels of the canvas are not one-to-one, the event triggering position is inaccurate, and you can use the scaleEventPoint method to make the event correct.
//The width of the canvas is half the canvas pixel
stage.scaleEventPoint(0.5, 0.5)
Example: https://github.com/dntzhang/cax/blob/master/packages/cax/examples/pie/main.js#L218-L220
Disable event detection for mouse or touch mobile. Default value in the web is false. You can change it:
stage.disableMoveDetection = true
Set the touchmove and mousemove detection interval by moveDetectionInterval.
//check twice in one second
stage.moveDetectionInterval = 500
const bitmap = new cax.Bitmap(img)
stage.add(bitmap)
stage.update()
If you only transmit URL instead of the instance of the Image object, you need to do this:
const bitmap = new cax.Bitmap('./wepay.png', ()=>{
stage.update()
})
stage.add(bitmap)
You can set the picture clipping display area, and other transform attributes:
bitmap.rect = [0, 0, 170, 140]
bitmap.x = 200
bitmap.rotation = 30
The sequence frame animation component can combine any region of any picture into a series of animations.
const sprite = new cax.Sprite({
framerate: 7,
imgs: ['./mario-sheet.png'],
frames: [
// x, y, width, height, originX, originY ,imageIndex
[0, 0, 32, 32],
[32 * 1, 0, 32, 32],
[32 * 2, 0, 32, 32],
[32 * 3, 0, 32, 32],
[32 * 4, 0, 32, 32],
[32 * 5, 0, 32, 32],
[32 * 6, 0, 32, 32],
[32 * 7, 0, 32, 32],
[32 * 8, 0, 32, 32],
[32 * 9, 0, 32, 32],
[32 * 10, 0, 32, 32],
[32 * 11, 0, 32, 32],
[32 * 12, 0, 32, 32],
[32 * 13, 0, 32, 32],
[32 * 14, 0, 32, 32]
],
animations: {
walk: {
frames: [0, 1]
},
happy: {
frames: [5, 6, 7, 8, 9]
},
win: {
frames: [12]
}
},
playOnce: false,
currentAnimation: "walk",
animationEnd: function () {
}
});
Jump to the current animationName and start playing
spriteObj.gotoAndPlay(animationName)
Jump to the current animationName and stop
spriteObj.gotoAndStop(animationName)
Jump to the current animationName and start playing, then destroy yourself after animation. Often used in explosions
spriteObj.gotoAndPlayOnce(animationName)
Text object
const text = new cax.Text('Hello World', {
font: '20px Arial',
color: '#ff7700',
baseline: 'top'
})
Get text width
textObj.getWidth()
The drawing object is used to draw graphics with Canvas instructions in the basic way of linking.
const graphics = new cax.Graphics()
graphics
.beginPath()
.arc(0, 0, 10, 0, Math.PI * 2)
.closePath()
.fillStyle('#f4862c')
.fill()
.strokeStyle('black')
.stroke()
graphics.x = 100
graphics.y = 200
stage.add(graphics)
In particular, if you perform a graphics connection rendering operation in a loop, be sure to add the clear () method, or the path will be overloaded to your browser:
cax.setInterval(function(){
graphics
.clear()
.beginPath()
.arc(0, 0, 10, 0, Math.PI * 2)
.stroke()
}, 16)
Unlike Graphics, Shape usually has limited width height, so it can be buffered with off screen Canvas. The following are Shape.
const rect = new cax.Rect(200, 100, {
fillStyle: 'black'
})
const circle = new cax.Circle(10)
const ellipse = new cax.Ellipse(120, 20)
Element is a combination of multiple elements, such as Bitmap, Group, Text, Shape and other mixed images.
const button = new cax.Button({
width: 100,
height: 40,
text: "Click Me!"
})
| name | Describe |
|---|---|
| x | Horizontal offset |
| y | Vertical offset |
| scaleX | Horizontal scaling |
| scaleY | Vertical scaling |
| scale | Horizontal and Vertical scaling |
| rotation | rotation |
| skewX | skewX |
| skewY | skewY |
| originX | Rotation base point X |
| originY | Rotation base point Y |
| Name | Describe |
|---|---|
| alpha | The transparency of the element |
Notice that the father and son have set up alpha to do multiplicative stacking.
| Name | Describe |
|---|---|
| compositeOperation | The superposition pattern drawn from the source image to the target image |
Notice that if you don't have a definition of compositeOperation to look up, find the nearest compositeOperation's parent container as its own compositeOperation.
| Name | Describe |
|---|---|
| cursor | The shape of the mouse |
| Name | Describe |
|---|---|
| fixed | Whether to fixed or not, the default is false, and set to true will not overlay the transform of ancestors. |
| Name | Describe |
|---|---|
| shadow | shadow |
Usage:
obj.shadow = {
color: '#42B035',
offsetX: -5,
offsetY: 5,
blur: 10
}
| Name | Describe |
|---|---|
| stage | get the root stage |
Usage:
obj.stage
Destroy self
obj.destroy()
| Name | Describe |
|---|---|
| click | Click time trigger on the element |
| mousedown | Triggers when the mouse button is pressed on the element |
| mousemove | Trigger when the mouse pointer moves to the element |
| mouseup | Trigger when the mouse button is released on the element |
| mouseover | Trigger when the mouse pointer moves to the element |
| mouseout | Trigger when the mouse pointer moves out of the element |
| tap | Leave the finger and leave immediately |
| touchstart | The start of finger touch action |
| touchmove | Move the finger after touch |
| touchend | End of finger touch action |
| drag | Drag and drop |
Cax has built-in to capability to write motion effects in a continuous way.
const easing = cax.To.easing.elasticInOut
cax.To.get(bitmap)
.to({ y: 340, rotation: 240 }, 2000, easing)
.begin(() => {
console.log("Task one has began!")
})
.progress(() => {
console.log("Task one is progressing!")
})
.end(() => {
console.log("Task one has completed!")
})
.wait(500)
.to()
.rotation(0, 1400, easing)
.begin(() => {
console.log("Task two has began!")
})
.progress(() => {
console.log("Task two is progressing!")
})
.end(() => {
console.log("Task two has completed!")
})
.start();
to and to are parallelto and wait are serialto and to is serial with the next to and toIf you want circular motion, you can use the cycle method:
cax.To.get(bitmap)
.to()
.y(340, 2000, cax.easing.elasticInOut)
.to
.y(0, 2000, cax.easing.elasticInOut)
.cycle()
.start()
It's important to note that, unlike tween.js, Cax uses the camelcase. For example, Cubic.In becomes cubicIn.
const stage = new cax.Stage(600, 400, 'body')
const bitmap = new cax.Bitmap('./wepay-diy.jpg', () => {
stage.update()
})
const clipPath = new cax.Graphics()
clipPath.arc(40, 40, 25, 0, Math.PI * 2)
bitmap.clip(clipPath)
stage.add(bitmap)
You can get the same effect with blow code:
const clipPath = new cax.Graphics()
clipPath.x = 40
clipPath.y = 40
clipPath.arc(0, 0, 25, 0, Math.PI * 2)
So you can find that clip graphics supports all the transformation props(x,y,scaleX,scaleY,rotation,skewX,skewY,originX,originY).
Custom Shape inherits from cax.Shape:
class Sector extends cax.Shape {
constructor (r, from, to, option) {
super()
this.option = option || {}
this.r = r
this.from = from
this.to = to
}
draw () {
this.beginPath()
.moveTo(0, 0)
.arc(0, 0, this.r, this.from, this.to)
.closePath()
.fillStyle(this.option.fillStyle)
.fill()
.strokeStyle(this.option.strokeStyle)
.lineWidth(this.option.lineWidth)
.stroke()
}
}
Use the Shape:
const sector = new Sector(10, 0, Math.PI/6, {
fillStyle: 'red'
lineWidth: 2
})
stage.add(sector)
stage.update()
Custom Element inherits from cax.Group:
class Button extends cax.Group {
constructor (option) {
super()
this.width = option.width
this.roundedRect = new cax.RoundedRect(option.width, option.height, option.r)
this.text = new cax.Text(option.text, {
font: option.font,
color: option.color
})
this.text.x = option.width / 2 - this.text.getWidth() / 2 * this.text.scaleX
this.text.y = option.height / 2 - 10 + 5 * this.text.scaleY
this.add(this.roundedRect, this.text)
}
}
export default Button
Use the Button:
const button = new cax.Button({
width: 100,
height: 40,
text: "Click Me!"
})
In general, it is suggested that inherit Group from a slightly complex combination, which is conducive to expansion and management of internal components.
MIT
