问题描述
通过为图层组件创建引用,我可以访问canvas元素,然后可以将其传递给caman函数,以将预设的滤镜应用于画布中的图像。但是,这可以按预期工作,将舞台保存为图像时,不应用滤镜。如何在应用Caman滤镜的情况下将Konva舞台导出为图像。
Component Editor.js
import React,{useRef} from 'react';
import {Stage,Layer,Image} from 'react-konva';
import EditorControls from './EditorControls';
const caman = window.Caman;
const Editor = ({image}) => {
const stageRef = useRef();
const mainLayer = useRef();
const filterSelect = filter => {
const canvas = mainLayer.current.canvas._canvas;
caman(canvas,image,function() {
this.revert();
if (!filter) {return;}
this[filter]().render();
});
}
return (
<div className='Editor'>
<Stage
width={500}
height={500}
ref={stageRef}
>
<Layer ref={mainLayer}>
<Image
x={0}
y={0}
width={500}
height={500}
image={image}
/>
</Layer>
</Stage>
<EditorControls
onFilterSelect={filterSelect}
/>
<button
onClick={() => {
const link = document.createElement('a');
link.download = 'test.png';
link.href = stageRef.current.getStage().toDataURL({pixelRatio: 3});
link.click();
link.remove();
}}
>
SAVE
</button>
</div>
);
}
export default Editor;
Component EditorControls.js
import React from 'react';
const filters = ['vintage','lomo','clarity','sinCity','sunrise','crossprocess','orangePeel','love','grungy','jarques','pinhole','oldBoot','glowingSun','hazyDays','herMajesty','nostalgia','hemingway','concentrate'];
const EditorControls = ({onFilterSelect}) => {
return (
<div className='EditorControls'>
<div className='EditorControls__filters'>
<button onClick={() => onFilterSelect('')}>
<p>noFilter</p>
</button>
{filters.map((filter,index) => (
<button key={filters[index]} onClick={() => onFilterSelect(filter)}>
<p>{filters[index]}</p>
</button>
))}
</div>
</div>
);
}
export default EditorControls;
解决方法
根据https://konvajs.org/docs/sandbox/Native_Context_Access.html,不建议手动更改画布内容(在您的情况下通过Caman操作)。
如果要申请Caman,您可以:
- 缓存节点并编写自己的自定义过滤器https://konvajs.org/docs/filters/Custom_Filter.html。要使其与Caman一起使用,您可以将Konva滤镜中使用的imageData转换为画布,然后应用Caman滤镜,然后再转换回imageData
- 或者,如果只想应用一次过滤器(导出时),则可以先使用node.toCanvas() method将节点转换为
<canvas>
元素。然后在Caman中使用生成的画布。