Touch event on Bitmap (coordinates and getPixel)

captFuture · by **captFuture** » Fri Feb 26, 2010 10:33 am

Hi guys,
For controlling my RGB multicolor LEDlamp I try developing an app that reads color values from a RGB color wheel image and displays the values as string over serial/bluetooth/wifi to the LED controller.

The connection stuff is pretty much done bit now I'm struggling getting the "colorpicker" to work.
My basic setup is a layout with 2 edit text fields for displaying the color values in RGB and Hex and an ImageView where a BitmapDrawable (from the colorwheel.png) is created

The Touch Event is set up - i can read the x and y of the canvas but can't access and read it from the Bitmap (and the getPixel for color values does not work as well)

Syntax: [ Download ] [ Hide ]

Using xml Syntax Highlighting

 
<?xml version="1.0" encoding="utf-8"?>
 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 
    android:orientation="vertical"
 
    android:layout_width="fill_parent"
 
    android:layout_height="fill_parent"
 
    android:background="#ffffff">
 
<TextView  
 
    android:layout_width="40px" 
 
    android:layout_height="wrap_content" 
 
    android:text="Hex:"
 
    android:textColor="#000000" 
 
    android:layout_marginLeft="10px"/>
 
<EditText android:text="@+id/EditText01" android:layout_marginLeft="10px" android:id="@+id/EditText01" android:layout_height="wrap_content" android:layout_width="200px"></EditText>
 
<TextView  
 
    android:layout_width="40px"
 
    android:layout_height="wrap_content"
 
    android:text="RGB:"
 
    android:textColor="#000000" 
 
    android:layout_marginLeft="10px"/>
 
<EditText android:text="@+id/EditText02" 
 
android:id="@+id/EditText02" 
 
android:layout_marginLeft="10px" 
 
android:layout_height="wrap_content"  
 
android:layout_width="200px">
 
</EditText>
 
<ImageView android:id="@+id/ImageView01" 
 
android:layout_width="wrap_content" 
 
android:layout_height="wrap_content" 
 
android:hapticFeedbackEnabled="true" 
 
android:focusableInTouchMode="true" 
 
android:scaleType="center"
 
android:clickable="true" android:layout_gravity="center">
 
</ImageView>
 
</LinearLayout>
 
Parsed in 0.005 seconds,  using GeSHi 1.0.8.4

Syntax: [ Download ] [ Hide ]

Using java Syntax Highlighting

 
package cap.pick.color;
 
import android.app.Activity;
 
import android.graphics.Bitmap;
 
import android.graphics.Color;
 
import android.graphics.drawable.BitmapDrawable;
 
import android.os.Bundle;
 
import android.view.MotionEvent;
 
import android.widget.ImageView;
 
import android.widget.TextView;
 
public class MyColorPicker extends Activity {
 
    public Float xtouch;
 
    public Float ytouch; 
 
    public TextView Hex;
 
    public TextView RGB; 
 
    public ImageView ImageView01;
 
    public BitmapDrawable bd;
 
    public Bitmap bitmap;
 
    /** Called when the activity is first created. */
 
    @Override
 
    public void onCreate(Bundle savedInstanceState) {
 
        super.onCreate(savedInstanceState);
 
        setContentView(R.layout.main);
 
        Hex = (TextView) findViewById(R.id.EditText01);
 
        RGB = (TextView) findViewById(R.id.EditText02);  
 
        ImageView myImageView = null;
 
        myImageView = (ImageView) findViewById(R.id.ImageView01);
 
        BitmapDrawable bd = (BitmapDrawable) myImageView.getResources().getDrawable(R.drawable.wheel);
 
        Bitmap bitmap = bd.getBitmap();
 
        myImageView.setImageBitmap(bitmap);
 
    }
 
    public boolean dispatchTouchEvent(MotionEvent event){
 
    // this is canvas x/y - for testing the touch event and it works
 
          xtouch = event.getX();
 
          ytouch = event.getY();
 
          RGB.setText(xtouch.toString());
 
          Hex.setText(ytouch.toString());
 
          // this is bitmap get color on x/y  - it doesn't work (app crashes)
 
          int color = bitmap.getPixel((int)event.getX(), (int)event.getY());
 
          RGB.setText(Color.red(color)+""+Color.green(color)+""+Color.blue(color));
 
          return true;
 
        }
 
}
 
Parsed in 0.035 seconds,  using GeSHi 1.0.8.4

I'm pretty stuck here - please help

pskink · by **pskink** » Fri Feb 26, 2010 1:11 pm

i've done similar color picker that operates on hsv model with optional alpha channel

i tried color wheel as well but decided tha picking from it would be inaccurate

see:
http://www.anddev.org/announce_color_pi ... 10771.html

captFuture · by **captFuture** » Fri Feb 26, 2010 2:09 pm

Thanks for your link - already did a "slider" based control, but this is too much "overhead" for an easy LEDcontrol and therefore i chose use a colorwheel now.

Cheers

pskink · by **pskink** » Fri Feb 26, 2010 2:31 pm

captFuture wrote:

Syntax: [ Download ] [ Hide ]
Syntax: [ Download ] [ Show ]
Using java Syntax Highlighting

package cap.pick.color;

import android.app.Activity;

import android.graphics.Bitmap;

import android.graphics.Color;

import android.graphics.drawable.BitmapDrawable;

import android.os.Bundle;

import android.view.MotionEvent;

import android.widget.ImageView;

import android.widget.TextView;

public class MyColorPicker extends Activity {

public Float xtouch;

public Float ytouch;

public TextView Hex;

public TextView RGB;

public ImageView ImageView01;

public BitmapDrawable bd;

public Bitmap bitmap;

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

Hex = (TextView) findViewById(R.id.EditText01);

RGB = (TextView) findViewById(R.id.EditText02);

ImageView myImageView = null;

myImageView = (ImageView) findViewById(R.id.ImageView01);

BitmapDrawable bd = (BitmapDrawable) myImageView.getResources().getDrawable(R.drawable.wheel);

Bitmap bitmap = bd.getBitmap();

myImageView.setImageBitmap(bitmap);

}

public boolean dispatchTouchEvent(MotionEvent event){

// this is canvas x/y - for testing the touch event and it works

xtouch = event.getX();

ytouch = event.getY();

RGB.setText(xtouch.toString());

Hex.setText(ytouch.toString());

// this is bitmap get color on x/y - it doesn't work (app crashes)

int color = bitmap.getPixel((int)event.getX(), (int)event.getY());

RGB.setText(Color.red(color)+""+Color.green(color)+""+Color.blue(color));

return true;

}

}

Parsed in 0.037 seconds, using GeSHi 1.0.8.4

this is because dispatchTouchEvent gets events where which position (0,0) is left/top corner of the root view of your activity not left/top of your image view

use myImageView.setOnTouchListener

captFuture · by **captFuture** » Fri Feb 26, 2010 3:31 pm

My newest version at least works... but with wrong color values - how do I correctly set this onTouchListener?

Syntax: [ Download ] [ Hide ]

Using java Syntax Highlighting

 
package cap.pick.color;
 
import android.app.Activity;
 
import android.graphics.Bitmap;
 
import android.graphics.Color;
 
import android.graphics.drawable.BitmapDrawable;
 
import android.os.Bundle;
 
import android.view.MotionEvent;
 
import android.widget.Button;
 
import android.widget.ImageView;
 
import android.widget.TextView;
 
public class MyColorPicker extends Activity {
 
    public TextView RGB; 
 
    public ImageView ImageView01;
 
    public Button BTN;
 
    public BitmapDrawable bd;
 
    public Bitmap bitmap; 
 
    /** Called when the activity is first created. */
 
    @Override
 
    public void onCreate(Bundle savedInstanceState) {
 
        super.onCreate(savedInstanceState);
 
        setContentView(R.layout.main);
 
        RGB = (TextView) findViewById(R.id.EditText02);  
 
        RGB.setText("please choose...");
 
        BTN = (Button) findViewById(R.id.Button01);
 
        BTN.setText("");
 
        BTN.setBackgroundColor(0xffffffff);
 
        ImageView myImageView = null;
 
        myImageView = (ImageView) findViewById(R.id.ImageView01);
 
        BitmapDrawable bd = (BitmapDrawable) myImageView.getResources().getDrawable(R.drawable.wheel);
 
        Bitmap bitmap = bd.getBitmap();
 
        myImageView.setImageBitmap(bitmap);
 
    }
 
  public boolean dispatchTouchEvent(MotionEvent event){
 
          ImageView myImageView = (ImageView) findViewById(R.id.ImageView01);
 
          BitmapDrawable bd = (BitmapDrawable) myImageView.getResources().getDrawable(R.drawable.wheel);
 
          Bitmap bitmap = bd.getBitmap();
 
          try{
 
                  int color = bitmap.getPixel((int)event.getX(),(int)event.getX());
 
                  RGB.setText(" R:"+Color.red(color)+" G:"+Color.green(color)+" B:"+Color.blue(color));
 
                  BTN.setBackgroundColor(color);
 
          } catch (Exception e){};
 
      return true;
 
        }
 
}
 
Parsed in 0.042 seconds,  using GeSHi 1.0.8.4

pskink · by **pskink** » Fri Feb 26, 2010 4:21 pm

captFuture wrote:My newest version at least works... but with wrong color values - how do I correctly set this onTouchListener?

myImageView.setOnTouchListener(this);

your Activity should implement OnTouchListener by overriding onTouch method.

all you did in dispatchTouchEvent move to onTouch

thats it.

-squid- · by **-squid-** » Thu Mar 25, 2010 1:57 am

Did you get this working with your lamp captFuture? !?

Touch event on Bitmap (coordinates and getPixel)

Touch event on Bitmap (coordinates and getPixel)

Re: Touch event on Bitmap (coordinates and getPixel)

captFuture

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