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Add undo & redo for annotations. (mozilla-services#4370, mozilla-serv…
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Original file line number | Diff line number | Diff line change |
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const { Selection } = require("../../../shared/selection"); | ||
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exports.EditorHistory = class { | ||
constructor(devicePixelRatio) { | ||
this.beforeEdits = []; | ||
this.afterEdits = []; | ||
this.devicePixelRatio = devicePixelRatio; | ||
} | ||
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push(canvas, area, recordType) { | ||
const record = new EditRecord( | ||
canvas, | ||
area, | ||
this.devicePixelRatio, | ||
recordType | ||
); | ||
this.beforeEdits.push(record); | ||
this.afterEdits = []; | ||
} | ||
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pushDiff(canvas, area) { | ||
this.push(canvas, area, RecordType.DIFF); | ||
} | ||
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pushFrame(canvas, area) { | ||
this.push(canvas, area, RecordType.FRAME); | ||
} | ||
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canUndo() { | ||
return !!this.beforeEdits.length; | ||
} | ||
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undo(canvasBeforeUndo) { | ||
if (!this.canUndo()) { | ||
return null; | ||
} | ||
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return this._replay(canvasBeforeUndo, this.beforeEdits, this.afterEdits); | ||
} | ||
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canRedo() { | ||
return !!this.afterEdits.length; | ||
} | ||
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redo(canvasBeforeRedo) { | ||
if (!this.canRedo()) { | ||
return null; | ||
} | ||
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return this._replay(canvasBeforeRedo, this.afterEdits, this.beforeEdits); | ||
} | ||
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_replay(canvasBeforeChange, from, to) { | ||
const fromRecord = from.pop(); | ||
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let area = fromRecord.area; | ||
if (fromRecord.recordType === RecordType.FRAME) { | ||
area = new Selection( | ||
0, 0, | ||
parseInt(canvasBeforeChange.style.width, 10), | ||
parseInt(canvasBeforeChange.style.height, 10) | ||
); | ||
} | ||
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const toRecord = new EditRecord( | ||
canvasBeforeChange, | ||
area, | ||
this.devicePixelRatio, | ||
fromRecord.recordType | ||
); | ||
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to.push(toRecord); | ||
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return fromRecord; | ||
} | ||
}; | ||
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class EditRecord { | ||
constructor(canvas, area, devicePixelRatio, recordType) { | ||
this.area = area; | ||
this.recordType = recordType; | ||
this.canvas = this.captureCanvas(canvas, area, devicePixelRatio, recordType); | ||
} | ||
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captureCanvas(canvas, area, devicePixelRatio, recordType) { | ||
const copy = document.createElement("canvas"); | ||
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if (recordType === RecordType.FRAME) { | ||
copy.width = canvas.width; | ||
copy.height = canvas.height; | ||
const copyContext = copy.getContext("2d"); | ||
copyContext.drawImage(canvas, 0, 0); | ||
return copy; | ||
} | ||
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copy.width = area.width; | ||
copy.height = area.height; | ||
const copyContext = copy.getContext("2d"); | ||
copyContext.drawImage( | ||
canvas, | ||
area.left * devicePixelRatio, | ||
area.top * devicePixelRatio, | ||
area.width * devicePixelRatio, | ||
area.height * devicePixelRatio, | ||
0, 0, area.width, area.height | ||
); | ||
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return copy; | ||
} | ||
} | ||
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const RecordType = { DIFF: 0, FRAME: 1 }; | ||
exports.RecordType = RecordType; |
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