# 触摸事件和键盘事件
转载:https://juejin.cn/post/6982387923266043941
# MouseEvent
<div id="box"></div>
const box = document.getElementById('box');
let isMouseDown = false;
// 将mousedown事件绑定到box元素上
box.addEventListener('mousedown', function (e) {
isMouseDown = true;
});
// 将mousemove事件绑定到document或window上,防止移动过快丢失目标元素
document.addEventListener('mousemove', function (e) {
if (isMouseDown) {
// todo
}
});
// 将mouseup事件绑定到document或window上,防止在目标元素外释放鼠标
document.addEventListener('mouseup', function (e) {
isMouseDown = false;
});
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# TouchEvent
<div id="box"></div>
const box = document.getElementById('box');
let point = { x: 0, y: 0 };
let point2 = { x: 0, y: 0 };
box.addEventListener('touchstart', function (e) {
point = { x: e.touches[0].clientX, y: e.touches[0].clientY };
// 第二个触摸点
if (pointers.length > 1) {
point2 = { x: e.touches[1].clientX, y: e.touches[1].clientY };
}
});
box.addEventListener('touchmove', function (e) {
const current = { x: e.touches[0].clientX, y: e.touches[0].clientY };
// 第二个触摸点
if (e.touches.length > 1) {
const current2 = { x: e.touches[1].clientX, y: e.touches[1].clientY };
}
});
box.addEventListener('touchend', function (e) { });
box.addEventListener('touchcancel', function (e) { });
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# PointEvent
<div id="box"></div>
const box = document.getElementById('box');
let isPointerDown = false;
box.addEventListener('pointerdown', function (e) {
isPointerDown = true;
});
box.addEventListener('pointermove', function (e) {
box.setPointerCapture(e.pointerId);
if (isPointerDown) {
// todo
}
});
box.addEventListener('pointerup', function (e) {
isPointerDown = false;
});
box.addEventListener('pointercancel', function (e) {
isPointerDown = false;
});
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# PointEvent 多点触控
<div id="box"></div>
const box = document.getElementById('box');
let pointers = [];
let point = { x: 0, y: 0 };
let point2 = { x: 0, y: 0 };
box.addEventListener('pointerdown', function (e) {
// 维护一个数组,用于记录当前触摸点
pointers.push(e);
point = { x: pointers[0].clientX, y: pointers[0].clientY };
// 第二个触摸点
if (pointers.length > 1) {
point2 = { x: pointers[1].clientX, y: pointers[1].clientY };
}
});
box.addEventListener('pointermove', function (e) {
handlePointers(e, 'update');
const current = { x: pointers[0].clientX, y: pointers[0].clientY };
if (pointers.length > 1) {
const current2 = { x: pointers[1].clientX, y: pointers[1].clientY };
}
});
box.addEventListener('pointerup', function (e) {
handlePointers(e, 'delete');
});
box.addEventListener('pointercancel', function (e) {
pointers = [];
});
/**
* 处理指针
* @param {PointerEvent} e
* @param {string} type
*/
function handlePointers(e, type) {
for (let i = 0; i < pointers.length; i++) {
if (pointers[i].pointerId === e.pointerId) {
if (type === 'update') {
pointers[i] = e;
} else if (type === 'delete') {
pointers.splice(i, 1);
}
}
}
}
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# 触摸和键盘
转:https://threejs.org/examples/#webgl_geometry_text
container.addEventListener( 'pointerdown', onPointerDown );
document.addEventListener( 'keypress', onDocumentKeyPress );
document.addEventListener( 'keydown', onDocumentKeyDown );
let pointerXOnPointerDown, pointerX,
function onPointerDown( event ) {
if ( event.isPrimary === false ) return;
pointerXOnPointerDown = event.clientX
document.addEventListener( 'pointermove', onPointerMove );
document.addEventListener( 'pointerup', onPointerUp );
}
function onPointerMove( event ) {
if ( event.isPrimary === false ) return;
pointerX = event.clientX
}
function onPointerUp() {
if ( event.isPrimary === false ) return;
document.removeEventListener( 'pointermove', onPointerMove );
document.removeEventListener( 'pointerup', onPointerUp );
}
function onDocumentKeyDown( event ) {
const keyCode = event.keyCode;
// backspace
if ( keyCode == 8 ) {
event.preventDefault();
text = text.substring( 0, text.length - 1 );
refreshText();
return false;
}
}
// chrome 下 keyCode == 8 是不会触发keypress
function onDocumentKeyPress( event ) {
const keyCode = event.which;
// backspace
if ( keyCode == 8 ) {
event.preventDefault();
} else {
const ch = String.fromCharCode( keyCode );
text += ch;
refreshText();
}
}
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← 累加函数