The previous article gave a brief introduction and usage examples of the canvas tag, but in fact the usage of canvas is very powerful. Many cool HTML5 animations and games are made based on canvas. . Therefore, I decided to continue writing two canvas-related blog posts to consolidate the foundation of canvas.
This article mainly introduces the related properties and usage of canvas.
Color, Style and Shading
Properties |
Description |
fillStyle |
Sets or returns the color, gradient, or pattern used for fill painting |
strokeStyle |
Sets or returns the color, gradient, or pattern used for strokes Gradient or pattern |
shadowColor |
Set or return the color used for shadow |
shadowBlur |
Set Or returns the blur level used for the shadow |
shadowOffsetX |
Sets or returns the horizontal distance of the shadow from the shape |
shadowOffsetY |
Sets or returns the vertical distance of the shadow from the shape |
Method |
Description |
createLinearGradient() |
Create a linear gradient (used on canvas content) |
createPattern() |
Repeat the specified element in the specified direction |
createRadialGradient() |
Create a radial/circular gradient (used on canvas content) |
addColorStop() |
Specify the color and stop position in the gradient object |
Line style
Properties |
Description |
lineCap |
Set or return the end endpoint style of the line |
lineJoin |
Set or return the corner type created when two lines intersect |
lineWidth |
Set or return the current line width |
miterLimit |
Set or return the maximum miter length |
Rectangle
Method |
Description |
##rect() | Create a rectangle |
fillRect() | Draw a "filled" rectangle |
strokeRect() | Draw a rectangle (no fill) |
clearRect() | Clear the specified pixels within the given rectangle |
Path
Method | Description |
fill() | Fill the current drawing (path) |
stroke() | Draw the defined path |
beginPath () | Start a path, or reset the current path |
moveTo() | Move the path to the specified point in the canvas, no Create a line |
closePath() | Create a path from the current point back to the starting point |
lineTo() | Add a new point and create a line in the canvas from that point to the last specified point |
clip() | Clip any from the original canvas Areas of shape and size |
quadraticCurveTo() | Creating quadratic Bezier curves |
bezierCurveTo() | Create cubic Bezier curve |
##arc()
Create arc/curve (used to create a circle or partial circle) |
|
arcTo()
Create an arc/curve between two tangents |
|
isPointInPath()
If specified Returns true if the point is in the current path, otherwise returns false |
|
Conversion
Method
Description |
|
scale()
Scale the current drawing to a larger or smaller size |
|
rotate()
Rotate the current drawing |
|
translate()
Remap the (0,0) position on the canvas |
|
transform()
Replace the current transformation matrix of the drawing |
|
setTransform()
Reset the current transformation to the identity matrix . Then run transform() |
|
Text
##PropertiesDescription | |
font
Set or return the current font attribute of the text content |
| textAlign
Set or return The current alignment of text content |
| textBaseline
Sets or returns the current text baseline used when drawing text |
|
Method |
Description |
##fillText() | On canvas Draw "filled" text |
strokeText() | Draw text on canvas (without fill) |
##measureText ()
Returns an object containing the specified text width |
|
Image drawing
Method
Description |
|
##drawImage()
Draw an image, canvas, or video to the canvas |
|
Pixel operations
PropertiesDescription |
|
width
Returns the width of the ImageData object |
| height
Returns the height of the ImageData object |
| data
Returns an object containing the image data for the specified ImageData object |
|
MethodDescription |
|
createImageData()
Create a new, blank ImageData object |
| getImageData()
Returns the ImageData object, which copies the pixel data for the specified rectangle on the canvas |
| putImageData()
Puts the image data (from the specified ImageData object ) placed back on the canvas |
|
Image combination
PropertiesDescription |
|
globalAlpha
Sets or returns the current alpha or transparency value of the drawing |
| globalCompositeOperation
Settings Or return how to draw a new image onto an existing image |
|
Other methods
MethodsDescription |
|
save()
Save the state of the current environment |
| restore()
Return the previously saved path status and attributes |
| createEvent()
|
| getContext()
Get the object used for drawing on the canvas |
| toDataURL()
Export the image drawn on the canvas element |
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The next section will use examples to illustrate the specific usage of each attribute and method.
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