How to proportionally adjust an image manually?

[RGBreality]

Hey, folks!

I need a little help thinking through some math (which I suck at)...

I'm using the Surface object to display images (such as BMPs, JPGs, and PNGs). I am in the process of setting up conditions such that if the image to be displayed is larger than the screen width (or screen height, or both), to adjust the image to "best fit" the screen.

What I am having problems with is calculating how to reduce an image proportionally. Since the Surface object doesn't offer an action to adjust size by percentage or scale, how can this be done manually? So, as a test example, if an image's width is wider than the screen's width, how would I determine what percentage to reduce the image's width (which I would then use to reduce the image's height by the same percentage)?

Pretty simple concept, I know... But I really suck at math...

Thanks for your help!

[nivram]

If you can get away with not using the surface object, the Picture Object will automatically adjust the photo to its size. For example:

User clicks on active system box 1
+String$("string")="flint"
--->Picure Object:new picture (this will be the location of your picture)

Marv

[LB]

Transform -> Resize -> X Size * Scale, Y Size * Scale
Where Scale is Min(Max Width*1.0/Normal Width, Max Height*1.0/Normal Height)

[nivram]

Transform -> Resize -> X Size * Scale, Y Size * Scale
Where Scale is Min(X Size / Max X, Y Size / Max Y)

(I think)

LB. If no one clutches their chest about this formula, I will add it to the Tech Manual. I believe it is a new one for the manual.

Marv

[Phi]

Whoa! That reminds me of my old unoptimised formula for ensuring a maths equation is calculated as a float.

Str$(Val(CompareIntegers$( "IIF", ReverseFind(List Line Text$( "Computing list", LoopIndex("Solve")-1), ".", 0), ">", -1, List Line Text$( "Computing list", LoopIndex("Solve")-1)+("0."+RepeatCharacters$( "Rep", "0", Len(List Line Text$( "Computing list", LoopIndex("Solve")-1))-ReverseFind(List Line Text$( "Computing list", LoopIndex("Solve")-1), ".", 0))),List Line Text$( "Computing list", LoopIndex("Solve")-1))+Val(CompareIntegers$( "IIF", ReverseFind(List Line Text$( "Computing list", LoopIndex("Solve")+1), ".", 0), ">", -1, List Line Text$( "Computing list", LoopIndex("Solve")+1)+("0."+RepeatCharacters$( "Rep", "0", Len(List Line Text$( "Computing list", LoopIndex("Solve")+1))-ReverseFind(List Line Text$( "Computing list", LoopIndex("Solve")+1), ".", 0))),List Line Text$( "Computing list", LoopIndex("Solve")+1)))))

I eventually reworked this. There was no way to make it small enough for MMF2 to accept as one expression, anyway.

EDIT: LB, do you need +0.0 in thar?

[LB]

Oops, the I had the formula backwards. Fixed now. I also added *1.0 (you could always wrap Max blah in parenthesis and add 0.0 to it for efficiency)

[RGBreality]

Hey, LB! As usual, you kick ass!

I'm not sure I created these actions correctly. So, I have an event which states under these conditions:


Surface object finishes loading image
Image width >= Screen width (as specified by the Windows Control object)
Image height < Screen height (as specified by the Windows Control object)

then perform these Surface object actions:
Set alterable value "Image Scale" to: Min((ScreenXSize( "Window Control" )*1.0/Width( "Surface" )), (ScreenYSize( "Window Control" )*1.0/Height( "Surface" )))
Resize editable image to: Width: Width( "Surface" )*Image Scale( "Surface" ) Height: Height( "Surface" )*Image Scale( "Surface" )

At run-time the image is not reduced in size. Did I do this correctly?


Thank you again for your help!

[LB]

I made a quick example:

[RGBreality]

Ah, LB! You make it look so easy! (Probably because for you, it is!)

Thanks again for being such a great teacher for MMF2!