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Allow switching between wheel/drag modes of the zoom #196

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Merged
merged 4 commits into from
Feb 4, 2019
Merged

Allow switching between wheel/drag modes of the zoom #196

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6ae4225
Enable switching between wheel/drag modes of the zoom
jledentu Jan 30, 2019
b7ad9f5
Remove comments (issue with htmllint)
jledentu Jan 30, 2019
2153996
Set samples functions into window to avoid ESLint errors
jledentu Jan 30, 2019
0e1a88a
Optimize mouse move handler + early return in the mouse up handler
jledentu Feb 4, 2019
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12 changes: 11 additions & 1 deletion samples/zoom-time.html
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@
<body>
<div style="width:75%;">
<button onclick="resetZoom()">Reset Zoom</button>
<button id="drag-switch" onclick="toggleDragMode()">Disable drag mode</button>
<canvas id="canvas"></canvas>
</div>
<script>
Expand Down Expand Up @@ -123,10 +124,19 @@
dataset.pointBorderWidth = 1;
});

window.resetZoom = function() {
window.myLine.resetZoom();
};

window.toggleDragMode = function() {
var zoomOptions = window.myLine.options.zoom;
zoomOptions.drag = !zoomOptions.drag;
document.getElementById('drag-switch').innerText = zoomOptions.drag ? 'Disable drag mode' : 'Enable drag mode';
};

window.onload = function() {
var ctx = document.getElementById('canvas').getContext('2d');
window.myLine = new window.Chart(ctx, config);

};
</script>
</body>
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132 changes: 69 additions & 63 deletions src/plugin.js
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Original file line number Diff line number Diff line change
Expand Up @@ -364,66 +364,73 @@ var zoomPlugin = {
if (!options.zoom || !options.zoom.enabled) {
return;
}
if (options.zoom.drag) {
chartInstance.zoom._mouseDownHandler = function(event) {

chartInstance.zoom._mouseDownHandler = function(event) {
if (chartInstance.options.zoom.drag) {
node.addEventListener('mousemove', chartInstance.zoom._mouseMoveHandler);
chartInstance.zoom._dragZoomStart = event;
};
node.addEventListener('mousedown', chartInstance.zoom._mouseDownHandler);
}
};
node.addEventListener('mousedown', chartInstance.zoom._mouseDownHandler);

chartInstance.zoom._mouseMoveHandler = function(event) {
if (chartInstance.zoom._dragZoomStart) {
chartInstance.zoom._dragZoomEnd = event;
chartInstance.update(0);
}
};
node.addEventListener('mousemove', chartInstance.zoom._mouseMoveHandler);

chartInstance.zoom._mouseUpHandler = function(event) {
if (chartInstance.zoom._dragZoomStart) {
var chartArea = chartInstance.chartArea;
var xAxis = getXAxis(chartInstance);
var yAxis = getYAxis(chartInstance);
var beginPoint = chartInstance.zoom._dragZoomStart;
var startX = xAxis.left;
var endX = xAxis.right;
var startY = yAxis.top;
var endY = yAxis.bottom;

if (directionEnabled(options.zoom.mode, 'x')) {
var offsetX = beginPoint.target.getBoundingClientRect().left;
startX = Math.min(beginPoint.clientX, event.clientX) - offsetX;
endX = Math.max(beginPoint.clientX, event.clientX) - offsetX;
}

if (directionEnabled(options.zoom.mode, 'y')) {
var offsetY = beginPoint.target.getBoundingClientRect().top;
startY = Math.min(beginPoint.clientY, event.clientY) - offsetY;
endY = Math.max(beginPoint.clientY, event.clientY) - offsetY;
}

var dragDistanceX = endX - startX;
var chartDistanceX = chartArea.right - chartArea.left;
var zoomX = 1 + ((chartDistanceX - dragDistanceX) / chartDistanceX);

var dragDistanceY = endY - startY;
var chartDistanceY = chartArea.bottom - chartArea.top;
var zoomY = 1 + ((chartDistanceY - dragDistanceY) / chartDistanceY);

// Remove drag start and end before chart update to stop drawing selected area
chartInstance.zoom._dragZoomStart = null;
chartInstance.zoom._dragZoomEnd = null;

if (dragDistanceX > 0 || dragDistanceY > 0) {
doZoom(chartInstance, zoomX, zoomY, {
x: (startX - chartArea.left) / (1 - dragDistanceX / chartDistanceX) + chartArea.left,
y: (startY - chartArea.top) / (1 - dragDistanceY / chartDistanceY) + chartArea.top
});
}
}
};
node.ownerDocument.addEventListener('mouseup', chartInstance.zoom._mouseUpHandler);
} else {
chartInstance.zoom._wheelHandler = function(event) {
chartInstance.zoom._mouseMoveHandler = function(event) {
if (chartInstance.options.zoom.drag && chartInstance.zoom._dragZoomStart) {
chartInstance.zoom._dragZoomEnd = event;
chartInstance.update(0);
}
};

chartInstance.zoom._mouseUpHandler = function(event) {
if (!chartInstance.options.zoom.drag || !chartInstance.zoom._dragZoomStart) {
return;
}

node.removeEventListener('mousemove', chartInstance.zoom._mouseMoveHandler);

var chartArea = chartInstance.chartArea;
var xAxis = getXAxis(chartInstance);
var yAxis = getYAxis(chartInstance);
var beginPoint = chartInstance.zoom._dragZoomStart;
var startX = xAxis.left;
var endX = xAxis.right;
var startY = yAxis.top;
var endY = yAxis.bottom;

if (directionEnabled(chartInstance.options.zoom.mode, 'x')) {
var offsetX = beginPoint.target.getBoundingClientRect().left;
startX = Math.min(beginPoint.clientX, event.clientX) - offsetX;
endX = Math.max(beginPoint.clientX, event.clientX) - offsetX;
}

if (directionEnabled(chartInstance.options.zoom.mode, 'y')) {
var offsetY = beginPoint.target.getBoundingClientRect().top;
startY = Math.min(beginPoint.clientY, event.clientY) - offsetY;
endY = Math.max(beginPoint.clientY, event.clientY) - offsetY;
}

var dragDistanceX = endX - startX;
var chartDistanceX = chartArea.right - chartArea.left;
var zoomX = 1 + ((chartDistanceX - dragDistanceX) / chartDistanceX);

var dragDistanceY = endY - startY;
var chartDistanceY = chartArea.bottom - chartArea.top;
var zoomY = 1 + ((chartDistanceY - dragDistanceY) / chartDistanceY);

// Remove drag start and end before chart update to stop drawing selected area
chartInstance.zoom._dragZoomStart = null;
chartInstance.zoom._dragZoomEnd = null;

if (dragDistanceX > 0 || dragDistanceY > 0) {
doZoom(chartInstance, zoomX, zoomY, {
x: (startX - chartArea.left) / (1 - dragDistanceX / chartDistanceX) + chartArea.left,
y: (startY - chartArea.top) / (1 - dragDistanceY / chartDistanceY) + chartArea.top
});
}
};
node.ownerDocument.addEventListener('mouseup', chartInstance.zoom._mouseUpHandler);

chartInstance.zoom._wheelHandler = function(event) {
if (!chartInstance.options.zoom.drag) {
var rect = event.target.getBoundingClientRect();
var offsetX = event.clientX - rect.left;
var offsetY = event.clientY - rect.top;
Expand All @@ -440,10 +447,10 @@ var zoomPlugin = {
}
// Prevent the event from triggering the default behavior (eg. Content scrolling).
event.preventDefault();
};
}
};

node.addEventListener('wheel', chartInstance.zoom._wheelHandler);
}
node.addEventListener('wheel', chartInstance.zoom._wheelHandler);

if (Hammer) {
var mc = new Hammer.Manager(node);
Expand Down Expand Up @@ -592,11 +599,10 @@ var zoomPlugin = {
var options = chartInstance.options;
var node = chartInstance.zoom.node;

if (options.zoom && options.zoom.drag) {
if (options.zoom) {
node.removeEventListener('mousedown', chartInstance.zoom._mouseDownHandler);
node.removeEventListener('mousemove', chartInstance.zoom._mouseMoveHandler);
node.ownerDocument.removeEventListener('mouseup', chartInstance.zoom._mouseUpHandler);
} else {
node.removeEventListener('wheel', chartInstance.zoom._wheelHandler);
}

Expand Down