How to save part of a bitmap

MaxApps · Feb 25, 2012

Hi

I am trying to save a part of a bitmap, but I cant get it right.
The following program almost does it, but there is one BIG problem.
The part of the image, that I am saving, should be 96dip x 64dip. That small part does get saved, but it gets filled with black around it and the bitmap ends up with 480x465.
Can someone tell me what is wrong?

canvas1.Initialize(Panel1)
Dim Bitmap1 As Bitmap
Bitmap1.Initialize(File.DirAssets, "1.jpg")
Dim DestRect As Rect
DestRect.Initialize(0dip, 0dip, 96dip, 64dip)

Dim name As String
Dim Out As OutputStream

Dim SrcRect As Rect
Dim Nummer As Int
SrcRect.Initialize(0, 0, 96, 64)
DestRect.Top = 0dip
DestRect.Bottom = 64dip
DestRect.Left = 0dip
DestRect.Right = 96dip
canvas1.DrawBitmap(Bitmap1, SrcRect, DestRect)
name="part1.png"
Out = File.OpenOutput(File.DirRootExternal, name, False)
canvas1.Bitmap.WriteToStream(Out, 100, "PNG")
Out.Close

Kind regards
Jakob

klaus · Feb 25, 2012

You should set the dimensions of the Panel to the dimensions of the bitmap you want save.

Best regards.

MaxApps · Feb 25, 2012

Panel1 is set to 96x64 (in the designer)

MaxApps · Feb 25, 2012

I have now added:

Panel1.Height=64dip
Panel1.Width=96dip

And that helped a lot. Now the bitmap ends up being 144x96
Why not 96x64?

klaus · Feb 25, 2012

Try to use an ImageView instead of the Panel. And save the ImageView.Bitmap and not the Canvas.Bitmap.

Best regards.

MaxApps · Feb 25, 2012

I dont know how to do that.
I cant write img.drawbitmap or img.bitmap.writetostream

Kind regards
Jakob

klaus · Feb 25, 2012

The attached example does it, with a Canvas drawing the partial image to a Bitmap.

Best regards.

MaxApps · Feb 25, 2012

Ok. I get it (the logic).

Thank you. :sign0188:

mkvidyashankar · Apr 28, 2012

How to Save the image which is visible on the imageview1

Hi

I am trying to save a bitmap which is visible on the imageview.

image is loaded to imageview from a selected file

then image is adjusted using pan and zoom ( using imageviewextras library)

the visible image should be saved.

I am trying to use canvas, but the whole image is saving again

please guide....:sign0085:

klaus · Apr 29, 2012

You should post your project as a zip file )IDE menu Files / Export As Zip)
Without the code we can't help.

Best regards.

mkvidyashankar · Apr 29, 2012

How to save Displayed image

Hi

Here is the code

B4X:

Sub imageset_click
  chooser.Show("image/*", "Choose image")
End Sub



Sub chooser_Result (Success As Boolean, Dir As String, FileName As String)
    seldir=Dir
   selfile=FileName
    If Success Then
       Panel_SELECTIMAGE.Visible=True
        Dim bmp As Bitmap
        bmp.Initialize(Dir, FileName)
      MyImageviewExtras.setBitmap(image_SELECTED,bmp)
      MyImageviewExtras.enablePanAndZoom(image_SELECTED)
      'image_SELECTED.Bitmap=LoadBitmap(Dir, FileName)
      
      'rc.writeBitmapToFile(bmp, filedefault,
      
      'Activity.SetBackgroundImage(bmp)
    Else
        ToastMessageShow("No image selected", True)
    End If
End Sub

After Zoom and pan a button is provided to save the displayed (pan and zoomed) image
here it is

B4X:

Sub Button_ok_Click
        Dim newfile As String
      Dim bmap2 As Bitmap
      Dim cs As Canvas
      'cs.Initialize(image_SELECTED)
      'bmap2.InitializeMutable(image_SELECTED.Width,image_SELECTED.Height)
'      'bmap2=image_SELECTED..Bitmap
'        Dim path1 As Path
'      path1.Initialize(image_SELECTED.left,image_SELECTED.top)
'      path1.LineTo(image_SELECTED.left+image_SELECTED.width,image_SELECTED.Top)
'      path1.LineTo(image_SELECTED.left+image_SELECTED.width,image_SELECTED.Top+image_SELECTED.Height)
'      path1.LineTo(image_SELECTED.left,image_SELECTED.Top+image_SELECTED.Height)
'      path1.Initialize(image_SELECTED.left,image_SELECTED.top)
'      cs.ClipPath(path1)
'      
      bmap2.Initialize3(image_SELECTED.Bitmap)
      newfile=DateTime.Now & ".jpg"
      
      rc.writeBitmapToFile(bmap2,filedefault,newfile,100)
       'File.Copy(seldir,selfile,filedefault,newfile)
      map2.Put("filepath",filedefault)
      map2.Put("imagefile",newfile)
      File.WriteMap(File.DirInternal, "alarmimage.ini", map2)
End Sub

Sub Button_cancel_Click
      ToastMessageShow("No image selected", True)
      Panel_SELECTIMAGE.Visible=False
End Sub

mkvidyashankar · May 5, 2012

Help please

:sign0085: Please

klaus · May 5, 2012

I think it would be easier and more efficient to help you if you posted your project as a zip file to see what you have done and what should be done.

Best regards.

mkvidyashankar · May 7, 2012

here is the file

Here is the file

I could not upload the whole project as it exceeds available limit
so i separated this module and uploaded

I am using ImageviewExtra to add pan and zoom functions to imageview
the main purpose of this module is to save selected part of the image which is displayed on the imageview

Please guide to solve the problem

mkvidyashankar · May 8, 2012

Saving part of image

:sign0085:

klaus · May 8, 2012

Sorry for not having answered yet, but I am on travel so no time to test your application. I'll be back on friday.

Best regards.

mkvidyashankar · May 8, 2012

Thank you klaus

waiting for your guidance

klaus · May 8, 2012

What are all the libraries you are using I don't have all of them installed yet.

Best regards.

mkvidyashankar · May 9, 2012

hi klaus

please download the updated zip file. I am using core, dialog, imageviewextras and phone library for this module

klaus · May 11, 2012

I had a look at your program.
You are using the ImageViewExtra library, but this one is no more available and replaced by the TouchViewExtra library.
The two functions you are using setBitmap and enablePanAndZoom are not in the new library. So I can't test the program in the same conditions.
Did you test the program you last posted ?
What are you doing with the MyImageviewExtras object ?

Best regards.

Best regards.

How to save part of a bitmap

Active Member

Expert

Active Member

Active Member

Expert

Active Member

Expert

Attachments

Active Member

Active Member

Expert

Active Member

Active Member

Expert

Active Member

Active Member

Expert

Active Member

Expert

Active Member

Expert

Privacy & Transparency

Privacy & Transparency