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/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.gallery3d.ui;
import android.content.Context;
import android.graphics.Rect;
import android.util.TypedValue;
import com.android.gallery3d.glrenderer.GLCanvas;
import com.android.gallery3d.glrenderer.NinePatchTexture;
public class ScrollBarView extends GLView {
@SuppressWarnings("unused")
private static final String TAG = "ScrollBarView";
private int mBarHeight;
private int mGripHeight;
private int mGripPosition; // left side of the grip
private int mGripWidth; // zero if the grip is disabled
private int mGivenGripWidth;
private int mContentPosition;
private int mContentTotal;
private NinePatchTexture mScrollBarTexture;
public ScrollBarView(Context context, int gripHeight, int gripWidth) {
TypedValue outValue = new TypedValue();
context.getTheme().resolveAttribute(
android.R.attr.scrollbarThumbHorizontal, outValue, true);
mScrollBarTexture = new NinePatchTexture(
context, outValue.resourceId);
mGripPosition = 0;
mGripWidth = 0;
mGivenGripWidth = gripWidth;
mGripHeight = gripHeight;
}
@Override
protected void onLayout(
boolean changed, int left, int top, int right, int bottom) {
if (!changed) return;
mBarHeight = bottom - top;
}
// The content position is between 0 to "total". The current position is
// in "position".
public void setContentPosition(int position, int total) {
if (position == mContentPosition && total == mContentTotal) {
return;
}
invalidate();
mContentPosition = position;
mContentTotal = total;
// If the grip cannot move, don't draw it.
if (mContentTotal <= 0) {
mGripPosition = 0;
mGripWidth = 0;
return;
}
// Map from the content range to scroll bar range.
//
// mContentTotal --> getWidth() - mGripWidth
// mContentPosition --> mGripPosition
mGripWidth = mGivenGripWidth;
float r = (getWidth() - mGripWidth) / (float) mContentTotal;
mGripPosition = Math.round(r * mContentPosition);
}
@Override
protected void render(GLCanvas canvas) {
super.render(canvas);
if (mGripWidth == 0) return;
Rect b = bounds();
int y = (mBarHeight - mGripHeight) / 2;
mScrollBarTexture.draw(canvas, mGripPosition, y, mGripWidth, mGripHeight);
}
}
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