// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
package org.chromium.components.paintpreview.player.frame;
import android.graphics.Matrix;
import android.graphics.Point;
import android.graphics.Rect;
import android.util.Size;
/**
* Used to represent the viewport for a frame in the paint preview player. There should be one of
* these objects per player frame and it should be shared between various classes that manipulated
* the location. Should only be accessed on the UI thread to avoid the need for locks.
*/
public class PlayerFrameViewport {
// Enforce a max tile size to avoid giant bitmaps. Most high-DPI displays are < 2500px in any
// dimension so this is a reasonable upper bound. Alternatively, this could use screensize, but
// then there is more complexity with rotation.
private static final int MAX_TILE_DIMENSION = 2500;
/** The size of the viewport. */
private Size mViewportSize = new Size(0, 0);
/** A 3x3 affine transformation matrix to track scale and translation. */
private final Matrix mViewportTransform = new Matrix();
/** The visible region of the viewport. */
private final Rect mVisibleRegion = new Rect();
/** The offset of the visible region of the viewport relative to the frame's origin. */
private final Point mOffset = new Point();
private boolean mTileSizeOverridden;
private Size mTileSize = new Size(0, 0);
/** Transient storage objects to avoid allocations. */
private final Rect mViewportRect = new Rect();
private final float[] mMatrixValues = new float[9];
private final Rect mVisibleViewport = new Rect();
/** @return the width of the viewport. */
public int getWidth() {
return mViewportSize.getWidth();
}
/** @return the height of the viewport. */
public int getHeight() {
return mViewportSize.getHeight();
}
/**
* Returns the translation of the viewport in the X direction (AKA left).
* @return the x translation of the viewport.
*/
float getTransX() {
mViewportTransform.getValues(mMatrixValues);
return mMatrixValues[Matrix.MTRANS_X];
}
/**
* Returns the translation of the viewport in the Y direction (AKA top).
* @return the y translation of the viewport.
*/
float getTransY() {
mViewportTransform.getValues(mMatrixValues);
return mMatrixValues[Matrix.MTRANS_Y];
}
/**
* Returns the scale at which to show contents.
* @return a scale factor for the viewport.
*/
public float getScale() {
mViewportTransform.getValues(mMatrixValues);
return mMatrixValues[Matrix.MSCALE_X]; // x and y should be identical here.
}
/**
* Returns the current viewport position as a rect. Use cautiously as this is an instantaneous
* snapshot and is not continually updated.
* @return a rect of the current viewport.
* */
public Rect asRect() {
mViewportTransform.getValues(mMatrixValues);
final int left = Math.round(mMatrixValues[Matrix.MTRANS_X]);
final int top = Math.round(mMatrixValues[Matrix.MTRANS_Y]);
mViewportRect.set(
left, top, left + mViewportSize.getWidth(), top + mViewportSize.getHeight());
return mViewportRect;
}
/**
* Sets the size of the viewport.
* @param width The width of the viewport.
* @param height The height of the viewport.
*/
void setSize(int width, int height) {
mViewportSize = new Size(width, height);
if (mTileSizeOverridden) return;
setTileSize(width, Math.round(height / 2f));
}
/**
* Sets the position x, y (left, top) of the viewport.
* @param x The left side of the viewport.
* @param y The top of the viewport.
*/
void setTrans(float x, float y) {
mViewportTransform.getValues(mMatrixValues);
mMatrixValues[Matrix.MTRANS_X] = x;
mMatrixValues[Matrix.MTRANS_Y] = y;
mViewportTransform.setValues(mMatrixValues);
}
/**
* Sets the scale of the viewport.
* @param scaleFactor The scale of the viewport.
*/
void setScale(float scaleFactor) {
mViewportTransform.getValues(mMatrixValues);
mMatrixValues[Matrix.MSCALE_X] = scaleFactor;
mMatrixValues[Matrix.MSCALE_Y] = scaleFactor;
mViewportTransform.setValues(mMatrixValues);
}
/**
* Offsets/shifts the viewport by a set amount.
* @param dx The distance to offset on the x-axis.
* @param dy The distance to offset on the y-axis.
*/
void offset(float dx, float dy) {
mViewportTransform.postTranslate(dx, dy);
}
/**
* Affine scaling of the viewport about a focal point/pivot.
* @param scaleFactor The amount to scale by (relative to the current scale).
* @param focalX The x-coordinate of the focal point.
* @param focalY The y-coordinate of the focal point.
*/
void scale(float scaleFactor, float focalX, float focalY) {
mViewportTransform.postScale(scaleFactor, scaleFactor, -focalX, -focalY);
}
/**
* Sets the visible portion of the viewport.
* @param left offset of the viewport on the left relative to the frame's origin.
* @param top offset of the viewport on the top relative to the frame's origin.
* @param right right - left is the width of the viewport.
* @param bottom bottom - top is the height of the viewport.
*/
void setVisibleRegion(int left, int top, int right, int bottom) {
mVisibleRegion.set(left, top, right, bottom);
mOffset.set(left, top);
}
/**
* Returns whether this frame is visible.
* @param isSubframe whether this is a subframe.
*/
boolean isVisible(boolean isSubframe) {
if (!isSubframe) return true;
return !mVisibleRegion.isEmpty();
}
/** Offset of the visible portion of the viewport relative to the frame's origin. */
Point getOffset() {
return mOffset;
}
/**
* Gets the visible viewport of the content.
* @param isSubframe whether this is a subframe.
* @return The rect of the visible viewport.
*/
Rect getVisibleViewport(boolean isSubframe) {
if (!isSubframe) return asRect();
if (mVisibleRegion.isEmpty()) return mVisibleRegion;
Rect vr = asRect();
final int x = vr.left + mVisibleRegion.left;
final int y = vr.top + mVisibleRegion.top;
mVisibleViewport.set(x, y, x + mVisibleRegion.width(), y + mVisibleRegion.height());
return mVisibleViewport;
}
/** @return bitmap tile size. */
Size getBitmapTileSize() {
return mTileSize;
}
/** Overrides the tile size. */
void overrideTileSize(int width, int height) {
setTileSize(width, height);
mTileSizeOverridden = true;
}
private void setTileSize(int width, int height) {
mTileSize =
new Size(Math.min(width, MAX_TILE_DIMENSION), Math.min(height, MAX_TILE_DIMENSION));
}
}
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