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Diffstat (limited to 'node_modules/react-dom/lib/TouchHistoryMath.js')
| -rw-r--r-- | node_modules/react-dom/lib/TouchHistoryMath.js | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/node_modules/react-dom/lib/TouchHistoryMath.js b/node_modules/react-dom/lib/TouchHistoryMath.js new file mode 100644 index 000000000..0755b0f9a --- /dev/null +++ b/node_modules/react-dom/lib/TouchHistoryMath.js @@ -0,0 +1,98 @@ +/** + */ + +'use strict'; + +var TouchHistoryMath = { + /** + * This code is optimized and not intended to look beautiful. This allows + * computing of touch centroids that have moved after `touchesChangedAfter` + * timeStamp. You can compute the current centroid involving all touches + * moves after `touchesChangedAfter`, or you can compute the previous + * centroid of all touches that were moved after `touchesChangedAfter`. + * + * @param {TouchHistoryMath} touchHistory Standard Responder touch track + * data. + * @param {number} touchesChangedAfter timeStamp after which moved touches + * are considered "actively moving" - not just "active". + * @param {boolean} isXAxis Consider `x` dimension vs. `y` dimension. + * @param {boolean} ofCurrent Compute current centroid for actively moving + * touches vs. previous centroid of now actively moving touches. + * @return {number} value of centroid in specified dimension. + */ + centroidDimension: function (touchHistory, touchesChangedAfter, isXAxis, ofCurrent) { + var touchBank = touchHistory.touchBank; + var total = 0; + var count = 0; + + var oneTouchData = touchHistory.numberActiveTouches === 1 ? touchHistory.touchBank[touchHistory.indexOfSingleActiveTouch] : null; + + if (oneTouchData !== null) { + if (oneTouchData.touchActive && oneTouchData.currentTimeStamp > touchesChangedAfter) { + total += ofCurrent && isXAxis ? oneTouchData.currentPageX : ofCurrent && !isXAxis ? oneTouchData.currentPageY : !ofCurrent && isXAxis ? oneTouchData.previousPageX : oneTouchData.previousPageY; + count = 1; + } + } else { + for (var i = 0; i < touchBank.length; i++) { + var touchTrack = touchBank[i]; + if (touchTrack !== null && touchTrack !== undefined && touchTrack.touchActive && touchTrack.currentTimeStamp >= touchesChangedAfter) { + var toAdd; // Yuck, program temporarily in invalid state. + if (ofCurrent && isXAxis) { + toAdd = touchTrack.currentPageX; + } else if (ofCurrent && !isXAxis) { + toAdd = touchTrack.currentPageY; + } else if (!ofCurrent && isXAxis) { + toAdd = touchTrack.previousPageX; + } else { + toAdd = touchTrack.previousPageY; + } + total += toAdd; + count++; + } + } + } + return count > 0 ? total / count : TouchHistoryMath.noCentroid; + }, + + currentCentroidXOfTouchesChangedAfter: function (touchHistory, touchesChangedAfter) { + return TouchHistoryMath.centroidDimension(touchHistory, touchesChangedAfter, true, // isXAxis + true // ofCurrent + ); + }, + + currentCentroidYOfTouchesChangedAfter: function (touchHistory, touchesChangedAfter) { + return TouchHistoryMath.centroidDimension(touchHistory, touchesChangedAfter, false, // isXAxis + true // ofCurrent + ); + }, + + previousCentroidXOfTouchesChangedAfter: function (touchHistory, touchesChangedAfter) { + return TouchHistoryMath.centroidDimension(touchHistory, touchesChangedAfter, true, // isXAxis + false // ofCurrent + ); + }, + + previousCentroidYOfTouchesChangedAfter: function (touchHistory, touchesChangedAfter) { + return TouchHistoryMath.centroidDimension(touchHistory, touchesChangedAfter, false, // isXAxis + false // ofCurrent + ); + }, + + currentCentroidX: function (touchHistory) { + return TouchHistoryMath.centroidDimension(touchHistory, 0, // touchesChangedAfter + true, // isXAxis + true // ofCurrent + ); + }, + + currentCentroidY: function (touchHistory) { + return TouchHistoryMath.centroidDimension(touchHistory, 0, // touchesChangedAfter + false, // isXAxis + true // ofCurrent + ); + }, + + noCentroid: -1 +}; + +module.exports = TouchHistoryMath;
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