/*
 * $URL: $
 * $Revision: $
 * $Date: $
 * $Author: tprochazka $
 * 
 * Author:  Tomáš Procházka <tomas.prochazka@atomsoft.cz>
 * Licence: Commercial
 */

package cz.atomsoft.android.test;

import android.content.Context;
import android.util.AttributeSet;

/**
 * Special version of ImageView which allow enlarge width of image if android:adjustViewBounds is true.
 * 
 * <p>This simulate HTML behaviour &lt;img src="" widh="100" /&gt;</p>
 * <p><a href="http://stackoverflow.com/questions/6202000/imageview-one-dimension-to-fit-free-space-and-second-evaluate-to-keep-aspect-rati">Stackoverflow question link</p>
 * 
 * @author Tomáš Procházka &lt;<a href="mailto:tomas.prochazka@atomsoft.cz">tomas.prochazka@atomsoft.cz</a>&gt;
 * @version $Revision: 0$ ($Date: 6.6.2011 18:16:52$)
 */
public class ImageView extends android.widget.ImageView {

	private int mDrawableWidth;
	private int mDrawableHeight;
	private boolean mAdjustViewBounds;
	private int mMaxWidth;
	private int mMaxHeight;

	public ImageView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
	}

	public ImageView(Context context, AttributeSet attrs) {
		super(context, attrs);
	}

	public ImageView(Context context) {
		super(context);
	}

	public void setAdjustViewBounds(boolean adjustViewBounds) {
		super.setAdjustViewBounds(adjustViewBounds);
		mAdjustViewBounds = adjustViewBounds;
	}

	public void setMaxWidth(int maxWidth) {
		super.setMaxWidth(maxWidth);
		mMaxWidth = maxWidth;
	}

	public void setMaxHeight(int maxHeight) {
		super.setMaxHeight(maxHeight);
		mMaxHeight = maxHeight;
	}

	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		super.onMeasure(widthMeasureSpec, heightMeasureSpec);

		mDrawableWidth = getDrawable().getIntrinsicWidth();
		mDrawableHeight = getDrawable().getIntrinsicHeight();

		int w = 0;
		int h = 0;

		// Desired aspect ratio of the view's contents (not including padding)
		float desiredAspect = 0.0f;

		// We are allowed to change the view's width
		boolean resizeWidth = false;

		// We are allowed to change the view's height
		boolean resizeHeight = false;

		if (mDrawableWidth > 0) {
			w = mDrawableWidth;
			h = mDrawableHeight;
			if (w <= 0) w = 1;
			if (h <= 0) h = 1;

			// We are supposed to adjust view bounds to match the aspect
			// ratio of our drawable. See if that is possible.
			if (mAdjustViewBounds) {

				int widthSpecMode = MeasureSpec.getMode(widthMeasureSpec);
				int heightSpecMode = MeasureSpec.getMode(heightMeasureSpec);

				resizeWidth = widthSpecMode != MeasureSpec.EXACTLY;
				resizeHeight = heightSpecMode != MeasureSpec.EXACTLY;

				desiredAspect = (float) w / (float) h;
			}
		}

		int pleft = getPaddingLeft();
		int pright = getPaddingRight();
		int ptop = getPaddingTop();
		int pbottom = getPaddingBottom();

		int widthSize;
		int heightSize;

		if (resizeWidth || resizeHeight) {
			/* If we get here, it means we want to resize to match the
			    drawables aspect ratio, and we have the freedom to change at
			    least one dimension. 
			*/

			// Get the max possible width given our constraints
			widthSize = resolveAdjustedSize(w + pleft + pright,
																								mMaxWidth, widthMeasureSpec);

			// Get the max possible height given our constraints
			heightSize = resolveAdjustedSize(h + ptop + pbottom,
																							mMaxHeight, heightMeasureSpec);

			if (desiredAspect != 0.0f) {
				// See what our actual aspect ratio is
				float actualAspect = (float) (widthSize - pleft - pright) /
																			(heightSize - ptop - pbottom);

				if (Math.abs(actualAspect - desiredAspect) > 0.0000001) {

					boolean done = false;

					// Try adjusting width to be proportional to height
					if (resizeWidth) {
						int newWidth = (int) (desiredAspect *
																					(heightSize - ptop - pbottom))
																					+ pleft + pright;
						if (newWidth <= widthSize) {
							widthSize = newWidth;
							done = true;
						}
					}

					// Try adjusting height to be proportional to width
					if (!done && resizeHeight) {
						int newHeight = (int) ((widthSize - pleft - pright)
																					/ desiredAspect) + ptop + pbottom;
						//if (newHeight <= heightSize) {
						heightSize = newHeight;
						//} 
					}
				}
			}
		} else {
			/* We are either don't want to preserve the drawables aspect ratio,
			   or we are not allowed to change view dimensions. Just measure in
			   the normal way.
			*/
			w += pleft + pright;
			h += ptop + pbottom;

			w = Math.max(w, getSuggestedMinimumWidth());
			h = Math.max(h, getSuggestedMinimumHeight());

			widthSize = resolveSize(w, widthMeasureSpec);
			heightSize = resolveSize(h, heightMeasureSpec);
		}

		setMeasuredDimension(widthSize, heightSize);
	}

	private int resolveAdjustedSize(int desiredSize, int maxSize,	int measureSpec) {
		int result = desiredSize;
		int specMode = MeasureSpec.getMode(measureSpec);
		int specSize = MeasureSpec.getSize(measureSpec);
		switch (specMode) {
		case MeasureSpec.UNSPECIFIED:
			/* Parent says we can be as big as we want. Just don't be larger
			than max size imposed on ourselves.
			*/
			result = Math.min(desiredSize, maxSize);
			break;
		case MeasureSpec.AT_MOST:
			// Parent says we can be as big as we want, up to specSize. 
			// Don't be larger than specSize, and don't be larger than 
			// the max size imposed on ourselves.
			result = Math.min(Math.min(desiredSize, specSize), maxSize);
			break;
		case MeasureSpec.EXACTLY:
			// No choice. Do what we are told.
			result = specSize;
			break;
		}
		return result;
	}
}