Chart.js/src/core/core.scaleService.js
Tanner Linsley c7107677d2 Stuck on shared vertical scale draw logic
Trying to make all scales share the same draw function for both
horizontal and vertical.  For some reason the vertical linear scale on
line.html has a width that is too small
2015-09-23 21:52:31 -06:00

320 lines
10 KiB
JavaScript

(function() {
"use strict";
var root = this,
Chart = root.Chart,
helpers = Chart.helpers;
// The scale service is used to resize charts along with all of their axes. We make this as
// a service where scales are registered with their respective charts so that changing the
// scales does not require
Chart.scaleService = {
// Scale registration object. Extensions can register new scale types (such as log or DB scales) and then
// use the new chart options to grab the correct scale
constructors: {},
// Use a registration function so that we can move to an ES6 map when we no longer need to support
// old browsers
// Scale config defaults
defaults: {},
registerScaleType: function(type, scaleConstructor, defaults) {
this.constructors[type] = scaleConstructor;
this.defaults[type] = helpers.extendDeep({}, Chart.defaults.scale, defaults);
},
getScaleConstructor: function(type) {
return this.constructors.hasOwnProperty(type) ? this.constructors[type] : undefined;
},
getScaleDefaults: function(type) {
return this.defaults.hasOwnProperty(type) ? this.defaults[type] : {};
},
// The interesting function
update: function(chartInstance, width, height) {
var xPadding = width > 30 ? 5 : 2;
var yPadding = height > 30 ? 5 : 2;
if (chartInstance) {
var leftScales = helpers.where(chartInstance.scales, function(scaleInstance) {
return scaleInstance.options.position == "left";
});
var rightScales = helpers.where(chartInstance.scales, function(scaleInstance) {
return scaleInstance.options.position == "right";
});
var topScales = helpers.where(chartInstance.scales, function(scaleInstance) {
return scaleInstance.options.position == "top";
});
var bottomScales = helpers.where(chartInstance.scales, function(scaleInstance) {
return scaleInstance.options.position == "bottom";
});
// Essentially we now have any number of scales on each of the 4 sides.
// Our canvas looks like the following.
// The areas L1 and L2 are the left axes. R1 is the right axis, T1 is the top axis and
// B1 is the bottom axis
// |------------------------------------------------------|
// | | T1 | |
// |----|-----|-------------------------------------|-----|
// | | | | |
// | L1 | L2 | Chart area | R1 |
// | | | | |
// | | | | |
// |----|-----|-------------------------------------|-----|
// | | B1 | |
// | | | |
// |------------------------------------------------------|
// What we do to find the best sizing, we do the following
// 1. Determine the minimum size of the chart area.
// 2. Split the remaining width equally between each vertical axis
// 3. Split the remaining height equally between each horizontal axis
// 4. Give each scale the maximum size it can be. The scale will return it's minimum size
// 5. Adjust the sizes of each axis based on it's minimum reported size.
// 6. Refit each axis
// 7. Position each axis in the final location
// 8. Tell the chart the final location of the chart area
// Step 1
var chartWidth = width / 2; // min 50%
var chartHeight = height / 2; // min 50%
chartWidth -= (2 * xPadding);
chartHeight -= (2 * yPadding);
// Step 2
var verticalScaleWidth = (width - chartWidth) / (leftScales.length + rightScales.length);
// Step 3
var horizontalScaleHeight = (height - chartHeight) / (topScales.length + bottomScales.length);
// Step 4;
var minimumScaleSizes = [];
var verticalScaleMinSizeFunction = function(scaleInstance) {
var minSize = scaleInstance.update(verticalScaleWidth, chartHeight);
minimumScaleSizes.push({
horizontal: false,
minSize: minSize,
scale: scaleInstance,
});
};
var horizontalScaleMinSizeFunction = function(scaleInstance) {
var minSize = scaleInstance.update(chartWidth, horizontalScaleHeight);
minimumScaleSizes.push({
horizontal: true,
minSize: minSize,
scale: scaleInstance,
});
};
// vertical scales
helpers.each(leftScales, verticalScaleMinSizeFunction);
helpers.each(rightScales, verticalScaleMinSizeFunction);
// horizontal scales
helpers.each(topScales, horizontalScaleMinSizeFunction);
helpers.each(bottomScales, horizontalScaleMinSizeFunction);
// Step 5
var maxChartHeight = height - (2 * yPadding);
var maxChartWidth = width - (2 * xPadding);
helpers.each(minimumScaleSizes, function(wrapper) {
if (wrapper.horizontal) {
maxChartHeight -= wrapper.minSize.height;
} else {
maxChartWidth -= wrapper.minSize.width;
}
});
// At this point, maxChartHeight and maxChartWidth are the size the chart area could
// be if the axes are drawn at their minimum sizes.
// Step 6
var verticalScaleFitFunction = function(scaleInstance) {
var wrapper = helpers.findNextWhere(minimumScaleSizes, function(wrapper) {
return wrapper.scale === scaleInstance;
});
if (wrapper) {
scaleInstance.update(wrapper.minSize.width, maxChartHeight);
}
};
var horizontalScaleFitFunction = function(scaleInstance) {
var wrapper = helpers.findNextWhere(minimumScaleSizes, function(wrapper) {
return wrapper.scale === scaleInstance;
});
var scaleMargin = {
left: totalLeftWidth,
right: totalRightWidth,
top: 0,
bottom: 0,
};
if (wrapper) {
scaleInstance.update(maxChartWidth, wrapper.minSize.height, scaleMargin);
}
};
var totalLeftWidth = xPadding;
var totalRightWidth = xPadding;
var totalTopHeight = yPadding;
var totalBottomHeight = yPadding;
helpers.each(leftScales, verticalScaleFitFunction);
helpers.each(rightScales, verticalScaleFitFunction);
// Figure out how much margin is on the left and right of the horizontal axes
helpers.each(leftScales, function(scaleInstance) {
totalLeftWidth += scaleInstance.width;
});
helpers.each(rightScales, function(scaleInstance) {
totalRightWidth += scaleInstance.width;
});
helpers.each(topScales, horizontalScaleFitFunction);
helpers.each(bottomScales, horizontalScaleFitFunction);
helpers.each(topScales, function(scaleInstance) {
totalTopHeight += scaleInstance.height;
});
helpers.each(bottomScales, function(scaleInstance) {
totalBottomHeight += scaleInstance.height;
});
// Let the left scale know the final margin
helpers.each(leftScales, function(scaleInstance) {
var wrapper = helpers.findNextWhere(minimumScaleSizes, function(wrapper) {
return wrapper.scale === scaleInstance;
});
var scaleMargin = {
left: 0,
right: 0,
top: totalTopHeight,
bottom: totalBottomHeight
};
if (wrapper) {
scaleInstance.update(wrapper.minSize.width, maxChartHeight, scaleMargin);
}
});
helpers.each(rightScales, function(scaleInstance) {
var wrapper = helpers.findNextWhere(minimumScaleSizes, function(wrapper) {
return wrapper.scale === scaleInstance;
});
var scaleMargin = {
left: 0,
right: 0,
top: totalTopHeight,
bottom: totalBottomHeight
};
if (wrapper) {
scaleInstance.update(wrapper.minSize.width, maxChartHeight, scaleMargin);
}
});
// Recalculate because the size of each scale might have changed slightly due to the margins (label rotation for instance)
totalLeftWidth = xPadding;
totalRightWidth = xPadding;
totalTopHeight = yPadding;
totalBottomHeight = yPadding;
helpers.each(leftScales, function(scaleInstance) {
totalLeftWidth += scaleInstance.width;
});
helpers.each(rightScales, function(scaleInstance) {
totalRightWidth += scaleInstance.width;
});
helpers.each(topScales, function(scaleInstance) {
totalTopHeight += scaleInstance.height;
});
helpers.each(bottomScales, function(scaleInstance) {
totalBottomHeight += scaleInstance.height;
});
// Figure out if our chart area changed. This would occur if the dataset scale label rotation
// changed due to the application of the margins in step 6. Since we can only get bigger, this is safe to do
// without calling `fit` again
var newMaxChartHeight = height - totalTopHeight - totalBottomHeight;
var newMaxChartWidth = width - totalLeftWidth - totalRightWidth;
if (newMaxChartWidth !== maxChartWidth || newMaxChartHeight !== maxChartHeight) {
helpers.each(leftScales, function(scale) {
scale.height = newMaxChartHeight;
});
helpers.each(rightScales, function(scale) {
scale.height = newMaxChartHeight;
});
helpers.each(topScales, function(scale) {
scale.width = newMaxChartWidth;
});
helpers.each(bottomScales, function(scale) {
scale.width = newMaxChartWidth;
});
maxChartHeight = newMaxChartHeight;
maxChartWidth = newMaxChartWidth;
}
// Step 7
// Position the scales
var left = xPadding;
var top = yPadding;
var right = 0;
var bottom = 0;
var verticalScalePlacer = function(scaleInstance) {
scaleInstance.left = left;
scaleInstance.right = left + scaleInstance.width;
scaleInstance.top = totalTopHeight;
scaleInstance.bottom = totalTopHeight + maxChartHeight;
// Move to next point
left = scaleInstance.right;
};
var horizontalScalePlacer = function(scaleInstance) {
scaleInstance.left = totalLeftWidth;
scaleInstance.right = totalLeftWidth + maxChartWidth;
scaleInstance.top = top;
scaleInstance.bottom = top + scaleInstance.height;
// Move to next point
top = scaleInstance.bottom;
};
helpers.each(leftScales, verticalScalePlacer);
helpers.each(topScales, horizontalScalePlacer);
// Account for chart width and height
left += maxChartWidth;
top += maxChartHeight;
helpers.each(rightScales, verticalScalePlacer);
helpers.each(bottomScales, horizontalScalePlacer);
// Step 8
chartInstance.chartArea = {
left: totalLeftWidth,
top: totalTopHeight,
right: totalLeftWidth + maxChartWidth,
bottom: totalTopHeight + maxChartHeight,
};
}
}
};
}).call(this);