Chapter 6, Problem 11PP

To complete this problem you must have a computer that is capable of viewing Scalable Vector Graphics (SVG) files. Your Web browser may already be able to view these files. To test to see if your browser can display SVG files, type in the rectline.svg file below and see if you can open it in your Web browser. If your Web browser cannot view the file, then you can search on the Web and download a free SVG viewer.

The graphics screen to draw an image uses a coordinate system in which (0, 0) is located in the upper-left corner. The x coordinate increases to the right, and the y coordinate increases to the bottom. Consequently, coordinate (100, 0) would be located 100 pixels directly toward the right from the upper-left corner, and coordinate (0, 100) would be located 100 pixels directly toward the bottom from the upper-left corner. This is illustrated in the figure below.

The SVG format defines a graphics image using XML. The specification for the image is stored in a text file and can be displayed by an SVG viewer. Here is a sample SVG file that draws two rectangles and a line. To view it, save it to a text file with the “.svg” extension, such as rectline.svg, and open it with your SVG viewer.

<?xml version="1.0" standalone="no"?> <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd"> <svg width="500" height="500" xmlns="http://www.w3.org/2000/svg"> <rect x="20" y="20" width="50" height="250" style="fill:blue;"/> <rect x="75" y="100" width="150" height="50" style="fill:rgb(0,255,0);"/> <line x1="0" y1="0" x2="300" y2="300" style="stroke:purple;stroke-width:2"/> </svg>

For purposes of this problem, you can ignore the first five lines and the last line and consider them “boilerplate” that must be inserted to properly create the image.

The lines that begins with <rect x="20"…draw a blue rectangle whose upper-left corner is at coordinate (20, 20) and whose width is 50 pixels and height is 250 pixels.

The lines that begin with <rect x="75"…draw a green rectangle (RGB color value of 0,255,0 is all green) whose upper-left corner is at coordinate (75, 100) and whose width is 150 pixels and height is 50 pixels.

Finally, the <line> tag draws a purple line from (0, 0) to (300, 300) with a width of 2.

Based on this example, write a program that inputs four nonnegative integer values and creates the SVG file that displays a simple bar chart that depicts the integer values. Your program should scale the values so they are always drawn with a maximum height of 400 pixels. For example, if your input values to graph were 20, 40, 60, and 120, you might generate a SVG file that would display as follows: