Created
October 24, 2014 16:47
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Scroll on drag with react-dnd
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configureDragDrop(registerType) { | |
var imageThreshold = Math.max(120, window.innerHeight / 4), | |
sectionThreshold = Math.max(140, window.innerHeight / 4), | |
currentDY = 0, | |
frame; | |
function makeScrollingHandler(threshold) { | |
function getScrollDY(clientY) { | |
var speed; | |
if (clientY < threshold) { | |
// -1 to 0 as we move from 0 to threshold | |
speed = -1 + clientY / threshold; | |
} else if (clientY > window.innerHeight - threshold) { | |
// 0 to 1 as we move from (innerHeight - threshold) to innerHeight | |
speed = 1 - (window.innerHeight - clientY) / threshold; | |
} else { | |
speed = 0; | |
} | |
return Math.round(speed * 10); | |
} | |
function tick() { | |
if (!currentDY) { | |
frame = null; | |
return; | |
} | |
window.scrollTo(0, getScrollY() + currentDY); | |
frame = window.requestAnimationFrame(tick); | |
} | |
function queueScroll(dy) { | |
currentDY = dy; | |
if (!frame) { | |
frame = window.requestAnimationFrame(tick); | |
} | |
} | |
function cancelScroll() { | |
window.cancelAnimationFrame(frame); | |
frame = null; | |
currentDY = 0; | |
} | |
return { | |
dropTarget: { | |
enter: cancelScroll, | |
leave: cancelScroll, | |
over(item, e) { | |
queueScroll(getScrollDY(e.clientY)); | |
}, | |
acceptDrop() { | |
cancelScroll(); | |
return false; | |
} | |
} | |
}; | |
} | |
registerType(DragItemTypes.SECTION, makeScrollingHandler(sectionThreshold)); | |
registerType(DragItemTypes.IMAGE, makeScrollingHandler(imageThreshold)); | |
}, |
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@gaearon Does this still work?