- #HOW TO CREATE A PIE CHART IN NUMBERS FOR MAC HOW TO#
- #HOW TO CREATE A PIE CHART IN NUMBERS FOR MAC UPDATE#
- #HOW TO CREATE A PIE CHART IN NUMBERS FOR MAC FULL#
Creating a Basic Bar GraphĪlthough the different types of charts may vary greatly in appearance, the underlying controls are very similar. You’ve also got a plethora of chart colors and styles, including customizable 3D graphics. There are several kinds of charts, such as bar graphs, line graphs, and pie charts.
#HOW TO CREATE A PIE CHART IN NUMBERS FOR MAC FULL#
If you need something more visual than a table full of data, you can use charts.
#HOW TO CREATE A PIE CHART IN NUMBERS FOR MAC HOW TO#
XScalar = (can.width - rowHead) / numSamples Ĭtx.strokeStyle="rgba(128, 128, 255, 0.In this chapter, you’ll learn how to create graphs and charts, including: set horizontal scalar to available width / number of samples YScalar = (can.height - colHead - margin) / (maxVal - minVal) set vertical scalar to available height / data points data sets - set literally or obtain from an ajax call The y-axis is scaled to -1 times the scalar, so the y-coordinate increases as you move up the graph. To plot a given sample number x, of value y, you can simply call lineTo(x,y). The example scales the canvas vertically to the range of sample values, and horizontally to the number of samples. All you have to do is supply the data and set a few variables, such as the minimum and maximum sample values, the number of samples, and any text for the column headers. This is especially useful for graphing rapidly changing data, real-time data, or user-entered data.Ī template for data plots is provided in Listing 10-3.
#HOW TO CREATE A PIE CHART IN NUMBERS FOR MAC UPDATE#
The advantage to using canvas for data plots, instead of drawing them using a graphics tool, is that you can update the artwork just by refreshing the data that it illustrates. A sample data plot is shown in Figure 10-1. If you have more than one data set, the data sets are usually color coded. Y = bottom - value * yScalar + yScalar * minVal Ī data plot is a graph showing your sample data plotted on a grid. YScalar = displayHeight / (maxVal - minVal) Listing 10-1 performs the transformation to scale the y-axis and position the zero point correctly, once you set the variables.ĭisplayHeight = can.height - topMargin - botMargin To scale the y-axis to fit your data using the transformation matrix, you need to know the minimum and maximum data values of your grid and the size of any header or footer area of the canvas that isn’t used for graphing. You need to use JavaScript to calculate the proper y-coordinates for your data. If your data needs to be plotted against a log scale instead of a linear scale, the transformation matrix won’t be much help-the matrix is for linear transforms. If you draw art or text on the canvas, positioned relative to the data, you need to use JavaScript to calculate the appropriate y-coordinates. You can either render the art or text before you change the transformation matrix, or you can save the context, graph the data, restore the context, and draw your text or art. If you include text or art on the canvas, you probably don’t want to transform the text or art using the matrix-it would be upside down and stretched vertically. Then your data value is the y-coordinate. The transformation matrix can flip the y-axis, scale the y-axis so the vertical display area equals your data range, and translate the y-axis zero point to the zero point for your data. If you are using a canvas element primarily as a grid, the easy way to fit your data to the grid is to use the transformation matrix. You can use a single canvas element for the whole chart, or you can use a canvas element just as a grid for the data, surrounding the grid with text and artwork using HTML and CSS, or positioning a canvas element inside of another canvas element using CSS. There is often text or artwork on the chart as well, including a vertical scale along the left edge. Scaling Your DataĪ graph or chart normally contains lines or bars plotted against a grid. This chapter shows you how to create data plots, bar graphs, and pie charts. If you’d prefer to use a JavaScript library, a web search for “canvas JavaScript libraries” or “canvas JavaScript libraries data visualization” will turn up a current list of libraries. This chapter shows you how to use the transformation matrix for graphing and how to calculate a y-coordinate for a data point on a graph. Use a data visualization JavaScript library. Write a routine that calculates a y-coordinate from the data. Use the transformation matrix to flip and scale the canvas’s y-axis. There are three common solutions for resolving y-coordinates for graphs and charts: Graphs are usually presented with the y-axis going up, not down, and the y-coordinates are scaled to fit the data, so you need a way to translate from the data value to a canvas y-coordinate. The main difficulty is scaling the data to fit neatly on the page. It’s easy to generate charts and graphs from data using the canvas element.
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