/**
* Copyright (C) 2013- Iordan Iordanov
*
* This is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this software; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
* USA.
*/
package com.undatech.opaque;
import com.undatech.opaque.R;
import android.graphics.Matrix;
public class CanvasZoomer {
static final String TAG = "CanvasZoomer";
RemoteCanvas canvas;
float minimumZoom;
float maximumZoom;
private Matrix matrix;
float zoomFactor;
public CanvasZoomer(RemoteCanvas canvas) {
this.canvas = canvas;
matrix = new Matrix();
zoomFactor = 1;
maximumZoom = 4;
}
public float getZoomFactor() {
return zoomFactor;
}
public void resetScaling () {
minimumZoom = canvas.getMinimumScale();
zoomFactor = 1.f;
reinitCanvasMatrix();
canvas.resetScroll();
}
private void reinitCanvasMatrix() {
canvas.computeShiftFromFullToView ();
matrix.reset();
matrix.preTranslate(-canvas.getShiftX(), -canvas.getShiftY());
matrix.postScale(zoomFactor, zoomFactor);
canvas.setImageMatrix(matrix);
}
public boolean changeZoom(float dZ) {
float newZoomFactor = zoomFactor * dZ;
// Ensure we're not going above or below the max and min zoom limits.
if (dZ < 1) {
if (newZoomFactor < minimumZoom) newZoomFactor = minimumZoom;
} else {
if (newZoomFactor > maximumZoom) newZoomFactor = maximumZoom;
}
// Here we do snapping to 1:1. If we are approaching scale = 1, we snap to it.
float oldZoomFactor = zoomFactor;
if ( (newZoomFactor > 0.95f && newZoomFactor < 1.00f) ||
(newZoomFactor > 1.00f && newZoomFactor < 1.05f) ) {
newZoomFactor = 1.f;
// Only if oldZoomFactor is outside the snap region, do we inform the user.
if (oldZoomFactor < 0.95f || oldZoomFactor > 1.05f)
canvas.displayShortToastMessage(R.string.snap_one_to_one);
}
zoomFactor = newZoomFactor;
reinitCanvasMatrix();
// Only if we have actually scaled do we pan and potentially set mouse position.
if (oldZoomFactor != newZoomFactor) {
return true;
} else {
return false;
}
}
}