To use macros in this file…
Reduce your security settings by changing Tools → Options → Security → Macro Security to Medium, and restart PowerPoint.
Start a default project in Visual Basic (the default name is Project1, don't change it)
Set form size to be 9000 by 9000, and set AutoRedraw to be True.
Visual BasicLoops
Loops are to avoid punishment
Private Sub Form_Click()
Form1.Print "I will not pass notes in class"
Form1.Print "I will not pass notes in class"
Form1.Print "I will not pass notes in class"
Form1.Print "I will not pass notes in class"
Form1.Print "I will not pass notes in class"
Form1.Print "I will not pass notes in class"
Form1.Print "I will not pass notes in class"
Form1.Print "I will not pass notes in class"
Form1.Print "I will not pass notes in class"
Form1.Print "I will not pass notes in class"
End Sub
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The better way to Repeat
Private Sub Form_Click()
For n=1 to 10
Form1.Print "I will not pass notes in class"
Next n
End Sub
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Repeating with one change
Private Sub Form_Click() Form1.Print "1 - I will not" Form1.Print "2 - I will not" Form1.Print "3 - I will not" Form1.Print "4 - I will not" Form1.Print "5 - I will not" Form1.Print "6 - I will not" Form1.Print "7 - I will not" Form1.Print "8 - I will not" Form1.Print "9 - I will not" Form1.Print "10 - I will not"End Sub
Private Sub Form_Click()
For n=1 to 10
Form1.Print n;
Form1.Print "- I will not"
Next n
End Sub
Run Loop
Run in VB
Writing Modular CodeFunctions and Subs
Top –Down ApproachPrivate Sub Form_Click()
DrawBoxDrawLines
End Sub
Private Sub DrawBox() Form1.Line (1000, 1000)-(1000, 8000) Form1.Line (1000, 8000)-(8000, 8000) Form1.Line (8000, 8000)-(8000, 1000) Form1.Line (8000, 1000)-(1000, 1000)End Sub
Private Sub DrawLines() Form1.Line (1000, 7000)-(2000, 1000) Form1.Line (1000, 6000)-(3000, 1000) Form1.Line (1000, 5000)-(4000, 1000) Form1.Line (1000, 4000)-(5000, 1000) Form1.Line (1000, 3000)-(6000, 1000) Form1.Line (1000, 2000)-(7000, 1000)End Sub
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Modular Code
• Increases Understandability– Giving long "imperative" (that means
commands as given by an imperial master) names makes for easy to follow programs
• Allows Code Reusability
• Improves Maintainability
Use loops (Be wasteful)Private Sub Form_Click()
DrawBoxDrawLines
End Sub
Private Sub DrawBox() Form1.Line (1000, 1000)-(1000, 8000) Form1.Line (1000, 8000)-(8000, 8000) Form1.Line (8000, 8000)-(8000, 1000) Form1.Line (8000, 1000)-(1000, 1000)End Sub
Private Sub DrawLines() For i=1000 to 8000 step 1000 Form1.Line (1000, 9000 - i)-(1000, i) Next iEnd Sub
OOPS!
The long code was…
Private Sub DrawLines() Form1.Line (1000, 7000)-(2000, 1000) Form1.Line (1000, 6000)-(3000, 1000) Form1.Line (1000, 5000)-(4000, 1000) Form1.Line (1000, 4000)-(5000, 1000) Form1.Line (1000, 3000)-(6000, 1000) Form1.Line (1000, 2000)-(7000, 1000)End Sub
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Use loops (Corrected)Private Sub Form_Click()
DrawBoxDrawLines
End Sub
Private Sub DrawBox() Form1.Line (1000, 1000)-(1000, 8000) Form1.Line (1000, 8000)-(8000, 8000) Form1.Line (8000, 8000)-(8000, 1000) Form1.Line (8000, 1000)-(1000, 1000)End Sub
Private Sub DrawLines() For i=1000 to 8000 step 1000 Form1.Line (1000, 9000 - i)-(I, 1000) Next iEnd Sub
The long code was…
Private Sub DrawLines() Form1.Line (1000, 7000)-(2000, 1000) Form1.Line (1000, 6000)-(3000, 1000) Form1.Line (1000, 5000)-(4000, 1000) Form1.Line (1000, 4000)-(5000, 1000) Form1.Line (1000, 3000)-(6000, 1000) Form1.Line (1000, 2000)-(7000, 1000)End Sub
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Use Arguments (not fights)
Private Sub Form_Click() DrawBox 1000, 8000 DrawBox 2000, 7000 DrawBox 3000, 6000 DrawBox 4000, 5000End Sub
Private Sub DrawBox(a, b) Form1.Line (a, a)-(a, b) Form1.Line (a, b)-(b, b) Form1.Line (b, b)-(b, a) Form1.Line (b, a)-(a, a)End Sub
Remember it used to be
Private Sub DrawBox() Form1.Line (1000, 1000)-(1000, 8000) Form1.Line (1000, 8000)-(8000, 8000) Form1.Line (8000, 8000)-(8000, 1000) Form1.Line (8000, 1000)-(1000, 1000)End Sub
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Modular Code
• Increases Understandability• Allows Code Reusability
– Writing a flexible general purpose Sub allows you to reuse the same code many times in the same program.
– You can also copy the same Sub to other programs if it does a useful thing.
– Documentation is important
• Improves Maintainability
Documentation
' Draws a square on Form1 with one corner at (a, a)
' and the other corner at (b, b)
Private Sub DrawBox(a, b)
Form1.Line (a, a)-(a, b)
Form1.Line (a, b)-(b, b)
Form1.Line (b, b)-(b, a)
Form1.Line (b, a)-(a, a)
End Sub
Use Arguments (not fights)Private Sub Form_Click() DrawBox 1000, 8000 DrawLines 1000, 8000, 100End Sub
Private Sub DrawBox(a, b) Form1.Line (a, a)-(a, b) Form1.Line (a, b)-(b, b) Form1.Line (b, b)-(b, a) Form1.Line (b, a)-(a, a)End Sub
Private Sub DrawLines(a,b,s) For i=a to b step s Form1.Line (a, a + b - i)-(i, a) Next iEnd Sub
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Dividing up a line
Suppose a line is (1,2)-(5,9)
Mid-point is (3, 5.5), but if five equal pieces?
1.0, 1.8, 2.6, 3.4, 4.2, 5.0
2.0, 3.4, 4.8, 6.2, 7.6, 9.0
The kth point in n pieces from (x0,y0)-(x1,y1) is given by the formula x = x0 + (x1 - x0)*k/n
y = y0 + (y1 - y0)*k/nwhere k can be from 0 to n
Local Variables are LocalPrivate Sub Form_Click() Form1.Line (1000, 2000)-(5000, 9000) Form1.Circle (1000, 2000), 100 Form1.Circle (1800, 3400), 100 Form1.Circle (2600, 4800), 100 Form1.Circle (3400, 6200), 100 Form1.Circle (4200, 7600), 100 Form1.Circle (5000, 9000), 100End Sub
Sub midx(k, n, x0, x1) x = x0 + (x1 - x0) * k / nEnd Sub
Sub midy(k, n, y0, y1) y = y0 + (y1 - y0) * k / nEnd Sub
Private Sub Form_Click() Form1.Line (1000, 2000)-(5000,
9000) For k = 0 To 5 midx k, 5, 1000, 5000 midy k, 5, 2000, 9000 Form1.Circle (x, y), 100 Next kEnd Sub
Run in VB
Run in VB
Global variables – Functions Dim x, ySub midx(k, n, x0, x1) x = x0 + (x1 - x0) * k / nEnd Sub
Sub midy(k, n, y0, y1) y = y0 + (y1 - y0) * k / nEnd Sub
Private Sub Form_Click() Form1.Line (1000, 2000)-(5000,
9000) For k=0 to 5 midx k, 5, 1000, 5000 midy k, 5, 2000, 9000 Form1.Circle (x, y), 100 Next kEnd Sub
Function Mid(k, n, a0, a1) Mid = a0 + (a1 - a0) * k / nEnd Function
Private Sub Form_Click() Form1.Line (1000, 2000)-
(5000, 9000) For k=0 to 5 x = mid( k, 5, 1000, 5000 ) y = mid( k, 5, 2000, 9000 ) Form1.Circle (x, y), 100 Next kEnd Sub
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Run in VB
Modular Code
• Increases Understandability
• Allows Code Reusability
• Improves Maintainability– If same code is repeated many places, and
corrections are made, it is easy to forget correcting all the places
Drawing our Web
Private Sub Form_Click() ax = 1000: ay = 1000 bx = 1000: by = 8000 cx = 8000: cy = 1000 dx = 1000: dy = 1000 For k=0 to 50 x0 = Mid(k, 50, ax, bx) y0 = Mid(k, 50, ay, by) x1 = Mid(k, 50, cx, dx) y1 = Mid(k, 50, cy, dy) Line (x0, y0)-(x1, y1) Next kEnd Sub
Function Mid(k, n, a0, a1) Mid = a0 + (a1 - a0) * k / nEnd Function
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Drawing Random WebsPrivate Sub Form_Click() ' Web 10, 1000, 1000, 1000,
8000, 8000, 1000, 1000, 1000 a = Rnd * 9000 b = Rnd * 9000 c = Rnd * 9000 d = Rnd * 9000 e = Rnd * 9000 f = Rnd * 9000 g = Rnd * 9000 h = Rnd * 9000 u = 5 + Rnd * 10 Web u, a, b, c, d, e, f, g, hEnd Sub
Sub Web(n, ax, ay, bx, by, cx, cy, dx, dy)
For k=0 to n x0 = Mid(k, n, ax, bx) y0 = Mid(k, n, ay, by) x1 = Mid(k, n, cx, dx) y1 = Mid(k, n, cy, dy) Line (x0, y0)-(x1, y1) Next kEnd Sub
Function Mid(k, n, a0, a1) Mid = a0 + (a1 - a0) * k / nEnd Function
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Challenge
Start with two different colors.
Slowly blend the colors from the first to the last color, using the same Mid function