Android Question Bitmap Brightness

Panagitois Lazos · Dec 28, 2014

Hi Everyone
Im trying to find a way to change an bitmaps brightness
but i couldent find any way .
is there a way to do it ?

Thanks !!

mangojack · Dec 29, 2014

This might be of Interest .. RS ImageProcessing
There is a .Brightness method.

For a simple method / workaround .. you could position a Black label over the image with its Alpha property set to around 80.
see here .. Image Opacity ...

Panagitois Lazos · Dec 29, 2014

Thanks Mango Jack! , i Did try RS ImageProcessing its Working, even though its a little slow when the image is big. but its the best way i found until now.

Panagitois Lazos · Jan 1, 2015

After a few research i found that the fastest way to do that is Renderscript.
Well i did find the proper RS and java to do it but i was unable ro make it work in b4a.
So here is the java

B4X:

Public Bitmap brightnessContrastRs(Bitmap bmIn, Int brightness, Int contrast)
{
    Bitmap bmOut = Bitmap.createBitmap(bmIn.getWidth(), bmIn.getHeight(),
            bmIn.getConfig());
    Allocation allocIn;
    allocIn = Allocation.createFromBitmap(rs, bmIn,
            Allocation.MipmapControl.MIPMAP_NONE,
            Allocation.USAGE_SCRIPT);
    Allocation allocOut = Allocation.createTyped(rs, allocIn.GetType());

    scriptCBrightnessContrast.set_in(allocIn);
    allocIn.destroy();
    scriptCBrightnessContrast.set_out(allocOut);
    scriptCBrightnessContrast.set_script(scriptCBrightnessContrast);
    Float rowContrast = ((100.0f + contrast) * (100.0f + contrast) / 10000.0f);
    Float rowBrightness = brightness / 255.f;
    scriptCBrightnessContrast.set_rowBrightness(rowBrightness);
    scriptCBrightnessContrast.set_rowContrast(rowContrast);
    scriptCBrightnessContrast.invoke_filter();
    allocOut.copyTo(bmOut);
    allocOut.destroy();
    Return bmOut;
}

and there is the Renderscript

B4X:

rs_allocation out;
rs_allocation In;
rs_script script;

Float rowBrightness;
Float rowContrast;

void root(Const uchar4* v_in, uchar4* v_out, Const void* usrData, uint32_t x,
          uint32_t y)
{
   float4 current = rsUnpackColor8888(*v_in);

   current.r = clamp(((clamp(current.r + rowBrightness, 0.0f, 1.0f) - 0.5f) * rowContrast + 0.5f), 0.0f, 1.0f);
   current.g = clamp(((clamp(current.g + rowBrightness, 0.0f, 1.0f)- 0.5f) * rowContrast + 0.5f), 0.0f, 1.0f);
   current.b = clamp(((clamp(current.b + rowBrightness, 0.0f, 1.0f) - 0.5f) * rowContrast + 0.5f), 0.0f, 1.0f);

   *v_out = rsPackColorTo8888(current.r, current.g, current.b, current.a);
}
void filter()
{
    #If !defined(RS_VERSION) || (RS_VERSION < 14)
       rsForEach(script, In, out, 0);
    #else
       rsForEach(script, In, out);
    #endif
}

does anyone done anything similar cause im completely confused on how to implement it in b4a.
Thanx guys!

Erel · Jan 1, 2015

Interesting.

Why not create a small Java library for this? It is not complicated.

It will be simpler in the next version of B4A which will allow you to embed Java code inside your code...

Panagitois Lazos · Jan 1, 2015

That Would be great, i ll give it a try and if succesfull i ll add a few more scripts, though it my first try and im not sure i can do it.

DonManfred · Jan 2, 2015

Erel said:
It will be simpler in the next version of B4A which will allow you to embed Java code inside your code...

Can you tell more about this?
When we will get this Update?
I hardly can wait

Erel · Jan 2, 2015

DonManfred said:
Can you tell more about this?

The idea is to allow you to add Java (or Objective C for B4i) code inside the project. You will then be able to call this code with CallSub or JavaObject.

B4X:

#If JAVA
public void SomeMethod(...) {
 ...
}
#End If

DonManfred said:
When we will get this Update?

It will take some time.

DonManfred · Jan 2, 2015

Sounds good

Let me ask one thing more please:

B4X:

#If JAVA
public void onCreate(...) {
...
}
public void onResume(...) {
...
}
#End If

Can we inject "subs" like this? I mean it will be called automatically in the java event when creating or deactivating a activity?

Erel · Jan 2, 2015

This code exactly will not work as these methods are already implemented. However I will provide a way to "hook into" these methods.

DonManfred · Jan 2, 2015

Erel said:
However I will provide a way to "hook into" these methods.

That´s what i wanted to ask... a way of hooking into such events sounds really great

Informatix · Jan 2, 2015

Panagitois Lazos said:
After a few research i found that the fastest way to do that is Renderscript.

In fact, the best way is to use libGDX with shaders (or directly OpenGL with shaders). There's a demo changing brightness and contrast provided with the library. It's so fast that it can be used in real-time.

Panagitois Lazos · Jan 2, 2015

Shaders are working Realy Fast my problem is that i want to change a bitmaps brightness witch i m displaying on a TouchImageView ,
so is there a way to change brightness of a bitmap in libgdx and then load it on a TouchImageView?

Informatix · Jan 2, 2015

Panagitois Lazos said:
Shaders are working Realy Fast my problem is that i want to change a bitmaps brightness witch i m displaying on a TouchImageView ,
so is there a way to change brightness of a bitmap in libgdx and then load it on a TouchImageView?

You don't need a TouchImageView if you use libGDX. Zooming in/out is very easy with libGDX.

Panagitois Lazos · Jan 2, 2015

true but i have to redesign my whole app , maybe ill consider it in the future

Informatix · Jan 2, 2015

Panagitois Lazos said:
true but i have to redesign my whole app , maybe ill consider it in the future

??? You replace just a view by another.

Panagitois Lazos · Jan 2, 2015

and then i ll have to implement touch zooming and moving and layers maybe its not that that hard but maybe in the future

Informatix · Jan 2, 2015

Erel said:
It will be simpler in the next version of B4A which will allow you to embed Java code inside your code...

This new year is starting very well.

Panagitois Lazos · Jan 2, 2015

So im Trying to use Simply Library Compiler to create a small lib with renderscript , the rs (kernel) file need to be in the root of the Java file
so it will be reflected with scriptC so how can i do that in library compiler ?.
any ideas ?
Please Forgive me if any of dont make sence itm my first try in library making , and i dont know java

Informatix · Jan 2, 2015

Panagitois Lazos said:
So im Trying to use Simply Library Compiler to create a small lib with renderscript , the rs (kernel) file need to be in the root of the Java file
so it will be reflected with scriptC so how can i do that in library compiler ?.
any ideas ?
Please Forgive me if any of dont make sence itm my first try in library making , and i dont know java

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