B4J Question Blurry ImageView after Rotation

xulihang

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Longtime User
I am trying to rotate an ImageView with the following code:

B4X: 
Dim view As B4XView = ImageView2
view.Rotation = -10

But the image becomes blurry. Are there any ideas on how to solve this?

I've also attached a test project.
 

Attachments

  • ViewRotation.zip
    2.2 KB · Views: 38
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teddybear

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Licensed User
Try this code

B4X: 
    ImageView2.As(JavaObject).RunMethod("setSmooth",Array(False))
    ImageView2.SetImage(Label1.Snapshot)
    Dim view As B4XView = ImageView2
    view.Rotation = -10
 
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xulihang

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Longtime User


It is still blurry.

B4X: 
    Dim jo As JavaObject = ImageView2
    jo.RunMethod("setSmooth",Array(False))
    ImageView1.SetImage(Label1.Snapshot)
    ImageView2.SetImage(Label1.Snapshot)
    Dim view As B4XView = ImageView2
    view.Rotation = -10
 
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xulihang

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I think it is inevitable that the text will become blurry after rotation because the image is resampled. The image has to be upscaled before rotation to solve the blurry problem.
 
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B

Brian Dean

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... because the image is resampled.
Click to expand...

But also with a truly horizontal or vertical line the character edge can be a transition between "fully on" and "fully off" pixels. If you want sloped text lines then you either retain fully on/off pixels and create a "stepped" effect, or you use partially coloured (antialiased) pixels which is what I think you are describibg as "blurry". Surely sloped text will always be less sharp overall than horizontal text.
 
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Daestrum

Expert
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Longtime User
Got to be honest they don't look blurry to me after running your example. Maybe it's the display - at 4K they are just as sharp, rotated or not.

you could try (for imageview)
B4X: 
    Dim view As B4XView = ImageView2
    view.As(JavaObject).RunMethod("setSmooth",Array(False))
    view.Rotation = -15
to see if it improves the image
 
Last edited:
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xulihang

Well-Known Member
Licensed User
Longtime User
Rotate the label and then take the snapshot instead of directly rotating the imageview. This seems to be the solution for me.

B4X: 
Dim lbl As B4XView = Label2
lbl.Rotation = -10
ImageView2.SetImage(Label2.Snapshot)
 
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