In my app, I want to be able to change the brightness of an image within an ImageView. I use seekbar for this purpose. It does change the brightness of the image when I move the scrollbar right but when I want to reduce the brightness and move left the brightness keeps increasing and the image become nearly white. Also it is so difficult to use the seekbar as a user. It doesn't move very smoothly. Can someone please help me to improve my code as I am a beginner in programming.
Here is part of the code:
On click of a button "filter" :
btn_filter.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Log.e("EditPhoto", "counter value = " + counter);
counter++;
sbarBrightness = (SeekBar) findViewById(R.id.seekBarForBrightness);
if (counter % 2 == 0) {
sbarBrightness.setVisibility(View.INVISIBLE);
} else {
sbarBrightness.setVisibility(View.VISIBLE);
}
sbarBrightness.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
int brightness;
@Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean
fromUser) {
brightness = progress;
imageBitmap = doBrightness(imageBitmap, brightness);
putGestureImageOnScreen(imageBitmap);
}
});
}
});
public static Bitmap doBrightness(Bitmap src, int value) {
Log.e("Brightness", "Changing brightnhjh");
int width = src.getWidth();
int height = src.getHeight();
Bitmap bmout = Bitmap.createBitmap(width, height, src.getConfig());
int A, R, G, B;
int pixel;
for (int i = 0; i < width; ++i) {
for (int j = 0; j < height; ++j) {
pixel = src.getPixel(i, j);
A = Color.alpha(pixel);
R = Color.red(pixel);
G = Color.green(pixel);
B = Color.blue(pixel);
R += value;
if (R > 255) {
R = 255;
} else if (R < 0) {
R = 0;
}
G += value;
if (G > 255) {
G = 255;
} else if (G < 0) {
G = 0;
}
B += value;
if (B > 255) {
B = 255;
} else if (B < 0) {
B = 0;
}
bmout.setPixel(i, j, Color.argb(A, R, G, B));
}
}
return bmout;
}
Seekbar's declaration in the layout:
<SeekBar
android:id="@+id/seekBarForBrightness"
android:layout_width="500dp"
android:layout_height="50dp"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
style="@style/tallerBarStyle"
android:layout_marginTop="64dp"
android:visibility="invisible" />
and this its style is as below:
<style name="tallerBarStyle" parent="@android:style/Widget.SeekBar">
<item name="android:indeterminateOnly">false</item>
<item name="android:progressDrawable">@android:drawable/progress_horizontal</item>
<item
name="android:indeterminateDrawable">@android:drawable/progress_horizontal</item>
<item name="android:minHeight">8dip</item>
<item name="android:maxHeight">10dip</item>
</style>
Also I want to save the brightness level of the image such that when I pass the image to another activity, the brighness is not lost. Can someone please guide me, how can I achieve it.
Thanks.
The problem is caused by doing manipulation on the same Bitmap
reference (imageBitmap = doBrightness(imageBitmap, brightness);
). Hence, when you drag the slider to the left, you're still continuously increasing the brightness to the image.
Try
brightness = progress;
//imageBitmap = doBrightness(imageBitmap, brightness);
putGestureImageOnScreen(doBrightness(imageBitmap, brightness));
For your 2nd question, you can use Intent
to transfer the brightness value to next Activity
and do the brightness manipulation once to get the same result.