I have a panel where I draw some squares, simulating street objects on a map. I use Scale (float f1, float f2) to enlarge the panel and the paintings. I have a ComboBox with 50%, 75%, 100%, 125%, 150%, and 200% items. The user can go from 50% to 200%, and return to 50%, if necessary. I need to know how to do this, if Scale () doesn't allow me to return to the previous position.
Resolved Control.Scale() and Control.UnScale()
- Thread starter diogenes
- Start date
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- Tags
- csharp winforms scale
Solution
Skydiver
Staff member
What have you tried so far? I would assume to scale to 50% you pass in 0.5, and to scale to 200% you pass in 2.0. Presumably passing in 0.5 will scale you to 50% again.
That's right. But the problem is that when I use the 50% (0.5) scale, it assumes that scale as 100%. So much so that if I use the Scale (0.5,0.5) again it will be 0.25 of the original size. I need that when I use 50% it should be the original size, and when I put 200% it should be the original size. This is to make a zoom effect, in the drawings made on the panel.
If you keep track of current scale you can revert to 100% by 1/current, and multiply that by new value to scale just once. Examples:
current scale is 25% and new scale is 125%: 1/0.25*1.25= factor 5
current scale is 200% and new scale is 25%: 1/2*0.25= factor 0.125
current scale is 25% and new scale is 125%: 1/0.25*1.25= factor 5
current scale is 200% and new scale is 25%: 1/2*0.25= factor 0.125
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