B4J Question How to Decrease Memory Consumption using HugeImageView

[xulihang]

I am trying to use HugeImageView to display this large image: https://upload.wikimedia.org/wikipedia/commons/8/8f/Whole_world_-_land_and_oceans_12000.jpg

The viewer experience is okay. But the memory consumption is high, about 4GB. How to decrease the memory consumption? Can we use the disk to cache the tiles?

 

[Swissmade]

Why not playing with this parameter starting Java?

-Xms128m -Xmx256m
Also you can check this with VisualVM

 

[xulihang]

If you set the max memory too low, it won't be able to load the image.

PS C:\Users\HP\Downloads\HugeImageView\B4J\Objects> java -Xmx512m  -jar .\HugeImageView.jar
Image size: 0x0
b4xpagesmanager._createpageifneeded (java line: 310)
java.lang.RuntimeException: java.lang.IllegalArgumentException: src cannot be null
        at anywheresoftware.b4a.keywords.Common.CallSub4(Common.java:522)
        at anywheresoftware.b4a.keywords.Common.CallSubNew2(Common.java:468)
        at b4j.example.b4xpagesmanager._createpageifneeded(b4xpagesmanager.java:310)
        at b4j.example.b4xpagesmanager._showpage(b4xpagesmanager.java:725)
        at b4j.example.b4xpagesmanager._addpage(b4xpagesmanager.java:116)
        at b4j.example.b4xpagesmanager._addpageandcreate(b4xpagesmanager.java:123)
        at b4j.example.b4xpagesmanager._initialize(b4xpagesmanager.java:494)
        at b4j.example.main._appstart(main.java:61)

 

[Swissmade]

If you set the max memory too low, it won't be able to load the image.

So play with it -Xms512m -Xmx1024m or more -Xms1024m -Xmx2048m

 

[xulihang]

No. You should optimize the code instead of setting the max memory.

 

[Swissmade]

No. You should optimize the code instead of setting the max memory.

Ok

 

[PaulMeuris]

The idea is to reduce the Java heap size and let the garbage collector (GC) do its job.
With this statement in the code the memory consumption is managed better than without it:

#Region Project Attributes
    #MainFormWidth: 600
    #MainFormHeight: 600
    #VirtualMachineArgs: -Xms2G -Xmx5G -XX:MinHeapFreeRatio=40 -XX:MaxHeapFreeRatio=70
#End Region

I have tested this with the HugeImageView example and the file you pointed to.
Maybe there is a Java specialist reading the forum that knows how to optimize the code further...

 

[Daestrum]

I tried with your image in a basic image view zooming in on a point at 12000,6000 showing an area of 1000 x 1000 pixels. I am using 523MB of memory.

 

[xulihang]

I think to fully load the image (24000x12000), this size of memory is needed. Maybe we can use javax.imageio.ImageReader to only read a sub region of the image instead of loading the entire image.

 

[Daestrum]

 

[Daestrum]

The code if you wanted to experiment (moving the viewport is trivial)

#Region Project Attributes
    #MainFormWidth: 600
    #MainFormHeight: 600
    '#JavaCompilerPath: 26, D:\jdk26\bin\javac.exe
#End Region

Sub Process_Globals
    Private fx As JFX
    Private MainForm As Form
    Private xui As XUI
    Private Button1 As B4XView
    Private ImageView1 As ImageView
    Private img As Image
    Private rect As JavaObject
End Sub

Sub AppStart (Form1 As Form, Args() As String)
    MainForm = Form1
    MainForm.RootPane.LoadLayout("Layout1")
    MainForm.Show
    img.Initialize("C:/temp","Whole_world_-_land_and_oceans_12000.jpg")
Log(img.Width & " x " & img.Height)
    rect.InitializeNewInstance("javafx.geometry.Rectangle2D",Array(12000.0,6000.0,1000.0,1000.0))
    ImageView1.SetImage(img)
    ImageView1.As(JavaObject).RunMethod("setViewport",Array(rect))
   
End Sub

Sub Button1_Click
    ' move viewport and tell imageview to use it
    rect.InitializeNewInstance("javafx.geometry.Rectangle2D",Array(12500.0,6000.0,1000.0,1000.0))
    ImageView1.As(JavaObject).RunMethod("setViewport",Array(rect))
End Sub

 

[xulihang]

Using a basic image view costs about 1100MB. But dragging it is lagging with this test project: https://www.b4x.com/android/forum/t...-the-center-in-scrollpane.169747/post-1039619

 

[xulihang]

I updated HugeImageView to use ImageReader to read a sub region of images. The memory usage is decreased from 4000MB to 2400MB. @Erel Could this improvement be added to the library?

 

[xulihang]

Another point to improve is this line:

XUIViewsUtils.SetBitmapAndFill(ZoomOutImageView, xui.LoadBitmapResize(Dir, Filename, ZoomOutSize, ZoomOutSize, True))

This line will read the full image. By providing a prescaled image, the memory usage can be lower than 200MB.

Check my test project here: https://www.b4x.com/android/forum/threads/putting-hugeimageview-inside-a-scrollpane.169827/