How do you scale a picture in an ImageWell such that it fits in the dimensions of the ImageWell?
Windows ?? OSX ??
OSX
ImageWell.Open
declare sub setImageScaling lib "Cocoa" selector "setImageScaling:" _
( handle as integer, value as integer )
setImageScaling( me.handle, 0 )
That sounds pretty Mac OS specific.
You may want to check the ProportionalScale method posted by Jay Madren at https://forum.xojo.com/17230-is-there-a-simple-way-such-as-property-method-to-scale-image-in
It can be used in a Desktop project, and works cross platform.
Hi Michel,
I am trying to use Jay Madren method at https://forum.xojo.com/17230-is-there-a-simple-way-such-as-property-method-to-scale-image-in as suggested by you in a Desktop project…
I created the function ProportionalScale
with Parameters extends Pic as Picture, Width as integer, Height as Integer
and Return Type Picture
I ran the project but got this…
“The extendsmodifiercannot be used a class method”
How can I fix that?
The code posted by Axel works great on Mac. Thanks Axel.
Is there a similar declare for Windows?
Thanks.
Lennox
I use this function for scaling:
Function ScaleImage(p as Picture, maxWidth as Integer, maxHeight as Integer) As Picture
// Scales a Picture while keeping the correct aspect ratio
If p <> Nil Then
// Calculate the scale ratio
Dim ratio As Double = min(maxHeight / p.height, maxWidth / p.width)
// Create a new picture to return
Dim newPic As New Picture(p.width * ratio, p.height * ratio)
// Draw picture in the new size
newPic.graphics.DrawPicture(p, 0, 0, newPic.width, newPic.height, 0, 0, p.width, p.height)
Return newPic
End If
End Function
2 Likes
Hi Marco,
I tried your function and called it like this in the DropObject event of the ImageWell
Dim ThePicture as Picture
ThePicture = Picture.Open(obj.folderitem)
Me.Image = ScaleImage(ThePicture, 124, 124)
does not work, maybe I am doing something incorrectly.
Kindly advise.
Thanks.
Lennox
Oh wait, an ImageWell.
I think these handle the image drop automatically. I don’t use those but I think you need to either somehow grab the image before it’s handled or get it out, resize and then back in.
I suggest using a canvas for this. Not sure if it’s easier but at least you have full control over it. Like this:
https://dl.dropboxusercontent.com/u/609785/Xojo/Forum/dropJpeg.xojo_binary_project
I do it this way:
Dim p as Picture
'assign image to p
p = app.ResizeToFit(p, ImageWell1.Width, ImageWell1.Height)
ImageWell1.Image = p
Function ResizeToFit(p as Picture, maxWidth as Integer, maxHeight as Integer) As Picture
if p <> nil then
’ Calculate the scale ratio
dim ratio as Double = min( maxHeight/p.height, maxWidth/p.width)
' Calculate new size
dim w as integer = p.width * ratio
dim h as integer = p.height * ratio
' Create a new picture to return
dim newPic as new Picture(w, h, 32)
' Draw picture in the new size
newPic.graphics.DrawPicture(p, 0, 0, w, h, 0, 0, p.width, p.height)
return newPic
else
return nil
end if
End Function
[quote=261220:@Lennox Jacob]I ran the project but got this…
“The extendsmodifiercannot be used a class method”[/quote]
You simply want to attach the method to a module and it will work as expected.
Thanks Marco,
I tried your project and it works, but I prefer an image well.
If I cannot get the other suggestions to work I may very well have to use your code, thanks again Marco.
Thanks Tony and Michel,
I just cannot get your suggestions to work, maybe I am doing something wrong.
I put the function in app and I am calling it from the Drop object of the ImageWell.
'' // ProportionalScale
-- proportionalScale had to be modified like this - I deleted extends because it would not compile...
"The extends modifier cannot be used a class method"
Function ProportionalScale(Pic as Picture, Width as integer, Height as Integer) As Picture
// Calculate scale factor
dim factor as Double = min( Height / Pic.Height, Width / Pic.Width )
// Calculate new size
dim w as integer = Pic.Width * factor
dim h as integer = Pic.Height * factor
// create new picture
dim NewPic as new Picture( w, h, 32 )
// draw picture in the new size
NewPic.Graphics.DrawPicture( Pic, 0, 0, w, h, 0, 0, Pic.Width, Pic.Height )
// return scaled image
Return NewPic
End Function
Dim ThePicture as Picture
ThePicture = Picture.Open(obj.folderitem)
Me.Image = app.ProportionalScale( ThePicture, ThePicture.Width, ThePicture.Height )
'// ScaleImage
Dim ThePicture as Picture
ThePicture = Picture.Open(obj.folderitem)
// MyImageView.Picture = MyImage.ProportionalScale( MyImageView.Width, MyImageView.Height ) was modified like this...
Me.Image = ScaleImage(ThePicture, 124, 124)
I will try it again.
Thanks again.
Lennox
OK, for an ImageWell DropObject event this is the workaround
https://forum.xojo.com/6298-scaling-dragged-image-to-imagewell/0
Michael Allen 8 Dec 2013 Sunnyvale, CA or elsewhere.
For Cocoa (Mavericks, Xojo 2013r3.3) builds the Imagewell momentarily displays the correctly scaled picture but then displays the unscaled picture.
See bug report 27149 - Cocoa ImageWell automatically adds the image to the well when dragging over.
As the bug report suggests it you move the “iwImage.Image = pPictureOut” into a timer you can work around the problem.
Lennox
Lennox. Read my post.
Instead of putting the function in App, drag a Module in the project, and drag the function to the module. Make sure it is Global, and then it will work just fine.
Extends cannot be used when a method is in in App or attached to a window, or a class. Hence the error.
Thanks Michel, I did not know that… “Extends cannot be used when a method is in in App or attached to a window, or a class”.
I’ll try your suggestion.
Thanks again.
Lennox
extend methods have to be in a module
Thanks Norman.
Lennox
Thanks Michel,
I tried your suggestion and it worked well.
Thanks again.
Lennox
[quote]
I use this function for scaling:
Function ScaleImage(p as Picture, maxWidth as Integer, maxHeight as Integer) As Picture
// Scales a Picture while keeping the correct aspect ratio
If p <> Nil Then
// Calculate the scale ratio
Dim ratio As Double = min(maxHeight / p.height, maxWidth / p.width)
// Create a new picture to return
Dim newPic As New Picture(p.width * ratio, p.height * ratio)
// Draw picture in the new size
newPic.graphics.DrawPicture(p, 0, 0, newPic.width, newPic.height, 0, 0, p.width, p.height)
Return newPic
End If
End Function[/quote]
Hello Marco,
Is a similar method as vb Pic.Scale(x1,y1)-(x2,y2) in xojo ?
No idea. 
The routine I posted is super basic.
If you want to resize a 300x300 picture half the size you tell it to resize to 150x150 and you’re done.
However, if you tell it to resize to 100x150, it will return a 100x100 picture because it keeps the aspect ratio in tact.
If you want a more advanced and better quality resizer, check this routine from Beatrix: https://forum.xojo.com/34206-resize-images-gocomics-uses-xojo/p1#p279702