W1502 Object Attributes
Prerequisites[edit]
Background[edit]
- Read Color (Wikipedia)
Prepare[edit]
Create a new Scenes shell project within your Experiences directory:
Enter the Sources/ScenesShell directory of the new project:
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Run the program.
ty-cam@codermerlin:~/Experiences/W1502/Sources/ScenesShell$ run
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Open a browser (or use a new tab on an already-open browser). Then, go to the URL: https://www.codermerlin.com/igis/user-name/
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Caution |
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You'll know you're successful if you see the title bar change to "Coder Merlin: IGIS". (The browser window will be blank because we haven't added any graphics yet.)
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Helpful Hint |
It's useful to bookmark this page in your browser. |
Experiment[edit]
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Stop the running program.
Return to the console and press CONTROL-C |
Open the file Background.swift in emacs.
Add a new method (below init) as follows:
override func setup(canvasSize:Size, canvas:Canvas) {
let rect = Rect(topLeft:Point(x:100, y:50), size:Size(width:200, height:300))
let rectangle = Rectangle(rect:rect)
let fillStyle = FillStyle(color:Color(.blue))
canvas.render(fillStyle, rectangle)
}
Remember to save the file, then suspend emacs.
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Helpful Hint |
Predefined color names may be found here: CSS Color Keywords, or, colors may be created by their RGB values using the constructor: Color(red:UInt8, green:UInt8, blue:UInt8)
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Run the program and refresh the browser page. |
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Observe, Ponder, and Journal : Section 1 |
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Stop the running program. |
Let's stroke the rectangle in green instead of filling it. Interrupt the running program and then resume emacs and edit the setup function so it appears as follows:
override func setup(canvasSize:Size, canvas:Canvas) {
let rect = Rect(topLeft:Point(x:100, y:50), size:Size(width:200, height:300))
let rectangle = Rectangle(rect:rect, fillMode:.stroke)
let strokeStyle = StrokeStyle(color:Color(.green))
canvas.render(strokeStyle, rectangle)
}
Remember to save the file, then suspend emacs.
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Run the program and refresh the browser page. |
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Observe, Ponder, and Journal : Section 2 |
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Stop the running program. |
Let's thicken the stroke line. Interrupt the running program and then resume emacs and add the following lines so that the entire function appears as:
override func setup(canvasSize:Size, canvas:Canvas) {
let rect = Rect(topLeft:Point(x:100, y:50), size:Size(width:200, height:300))
let rectangle = Rectangle(rect:rect, fillMode:.stroke)
let strokeStyle = StrokeStyle(color:Color(.green))
let lineWidth = LineWidth(width:5)
canvas.render(strokeStyle, lineWidth, rectangle)
}
Remember to save the file, then suspend emacs.
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Run the program and refresh the browser page. |
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Observe, Ponder, and Journal : Section 3 |
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Stop the running program. |
Finally, let's both stroke and fill simultaneously. Interrupt the running program and then resume emacs and add the following lines so that the entire function appears as:
override func setup(canvasSize:Size, canvas:Canvas) {
let rect = Rect(topLeft:Point(x:100, y:50), size:Size(width:200, height:300))
let rectangle = Rectangle(rect:rect, fillMode:.fillAndStroke)
let fillStyle = FillStyle(color:Color(.green))
let strokeStyle = StrokeStyle(color:Color(.blue))
let lineWidth = LineWidth(width:5)
canvas.render(fillStyle, strokeStyle, lineWidth, rectangle)
}
Remember to save the file, then suspend emacs.
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Run the program and refresh the browser page. |
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Observe, Ponder, and Journal : Section 4 |
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Stop the running program. |
Before beginning the exercises, remove the above code and then recreate your skyscrapers (and only your skyscrapers) from the previous experience. (You may copy/paste the required code from W1501 Introduction to Objects.)
Exercises[edit]
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Exercises |
When done, you must have at least seven different colors on your canvas. |