1 files changed, 282 insertions, 0 deletions
diff --git a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/gfx/ImmutableViewportMetrics.java b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/gfx/ImmutableViewportMetrics.java
new file mode 100644
index 000000000..8072deecc
--- /dev/null
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/gfx/ImmutableViewportMetrics.java
@@ -0,0 +1,282 @@
+/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.gfx;
+
+import org.mozilla.gecko.annotation.WrapForJNI;
+import org.mozilla.gecko.util.FloatUtils;
+
+import android.graphics.PointF;
+import android.graphics.RectF;
+import android.util.DisplayMetrics;
+
+/**
+ * ImmutableViewportMetrics are used to store the viewport metrics
+ * in way that we can access a version of them from multiple threads
+ * without having to take a lock
+ */
+public class ImmutableViewportMetrics {
+
+    // We need to flatten the RectF and FloatSize structures
+    // because Java doesn't have the concept of const classes
+    public final float pageRectLeft;
+    public final float pageRectTop;
+    public final float pageRectRight;
+    public final float pageRectBottom;
+    public final float cssPageRectLeft;
+    public final float cssPageRectTop;
+    public final float cssPageRectRight;
+    public final float cssPageRectBottom;
+    public final float viewportRectLeft;
+    public final float viewportRectTop;
+    public final int viewportRectWidth;
+    public final int viewportRectHeight;
+
+    public final float zoomFactor;
+
+    public ImmutableViewportMetrics(DisplayMetrics metrics) {
+        viewportRectLeft   = pageRectLeft   = cssPageRectLeft   = 0;
+        viewportRectTop    = pageRectTop    = cssPageRectTop    = 0;
+        viewportRectWidth = metrics.widthPixels;
+        viewportRectHeight = metrics.heightPixels;
+        pageRectRight  = cssPageRectRight  = metrics.widthPixels;
+        pageRectBottom = cssPageRectBottom = metrics.heightPixels;
+        zoomFactor = 1.0f;
+    }
+
+    /** This constructor is used by native code in AndroidJavaWrappers.cpp, be
+     * careful when modifying the signature.
+     */
+    @WrapForJNI(calledFrom = "gecko")
+    private ImmutableViewportMetrics(float aPageRectLeft, float aPageRectTop,
+        float aPageRectRight, float aPageRectBottom, float aCssPageRectLeft,
+        float aCssPageRectTop, float aCssPageRectRight, float aCssPageRectBottom,
+        float aViewportRectLeft, float aViewportRectTop, int aViewportRectWidth,
+        int aViewportRectHeight, float aZoomFactor)
+    {
+        pageRectLeft = aPageRectLeft;
+        pageRectTop = aPageRectTop;
+        pageRectRight = aPageRectRight;
+        pageRectBottom = aPageRectBottom;
+        cssPageRectLeft = aCssPageRectLeft;
+        cssPageRectTop = aCssPageRectTop;
+        cssPageRectRight = aCssPageRectRight;
+        cssPageRectBottom = aCssPageRectBottom;
+        viewportRectLeft = aViewportRectLeft;
+        viewportRectTop = aViewportRectTop;
+        viewportRectWidth = aViewportRectWidth;
+        viewportRectHeight = aViewportRectHeight;
+        zoomFactor = aZoomFactor;
+    }
+
+    public float getWidth() {
+        return viewportRectWidth;
+    }
+
+    public float getHeight() {
+        return viewportRectHeight;
+    }
+
+    public float viewportRectRight() {
+        return viewportRectLeft + viewportRectWidth;
+    }
+
+    public float viewportRectBottom() {
+        return viewportRectTop + viewportRectHeight;
+    }
+
+    public PointF getOrigin() {
+        return new PointF(viewportRectLeft, viewportRectTop);
+    }
+
+    public FloatSize getSize() {
+        return new FloatSize(viewportRectWidth, viewportRectHeight);
+    }
+
+    public RectF getViewport() {
+        return new RectF(viewportRectLeft,
+                         viewportRectTop,
+                         viewportRectRight(),
+                         viewportRectBottom());
+    }
+
+    public RectF getCssViewport() {
+        return RectUtils.scale(getViewport(), 1 / zoomFactor);
+    }
+
+    public RectF getPageRect() {
+        return new RectF(pageRectLeft, pageRectTop, pageRectRight, pageRectBottom);
+    }
+
+    public float getPageWidth() {
+        return pageRectRight - pageRectLeft;
+    }
+
+    public float getPageHeight() {
+        return pageRectBottom - pageRectTop;
+    }
+
+    public RectF getCssPageRect() {
+        return new RectF(cssPageRectLeft, cssPageRectTop, cssPageRectRight, cssPageRectBottom);
+    }
+
+    public RectF getOverscroll() {
+        return new RectF(Math.max(0, pageRectLeft - viewportRectLeft),
+                         Math.max(0, pageRectTop - viewportRectTop),
+                         Math.max(0, viewportRectRight() - pageRectRight),
+                         Math.max(0, viewportRectBottom() - pageRectBottom));
+    }
+
+    /*
+     * Returns the viewport metrics that represent a linear transition between "this" and "to" at
+     * time "t", which is on the scale [0, 1). This function interpolates all values stored in
+     * the viewport metrics.
+     */
+    public ImmutableViewportMetrics interpolate(ImmutableViewportMetrics to, float t) {
+        return new ImmutableViewportMetrics(
+            FloatUtils.interpolate(pageRectLeft, to.pageRectLeft, t),
+            FloatUtils.interpolate(pageRectTop, to.pageRectTop, t),
+            FloatUtils.interpolate(pageRectRight, to.pageRectRight, t),
+            FloatUtils.interpolate(pageRectBottom, to.pageRectBottom, t),
+            FloatUtils.interpolate(cssPageRectLeft, to.cssPageRectLeft, t),
+            FloatUtils.interpolate(cssPageRectTop, to.cssPageRectTop, t),
+            FloatUtils.interpolate(cssPageRectRight, to.cssPageRectRight, t),
+            FloatUtils.interpolate(cssPageRectBottom, to.cssPageRectBottom, t),
+            FloatUtils.interpolate(viewportRectLeft, to.viewportRectLeft, t),
+            FloatUtils.interpolate(viewportRectTop, to.viewportRectTop, t),
+            (int)FloatUtils.interpolate(viewportRectWidth, to.viewportRectWidth, t),
+            (int)FloatUtils.interpolate(viewportRectHeight, to.viewportRectHeight, t),
+            FloatUtils.interpolate(zoomFactor, to.zoomFactor, t));
+    }
+
+    public ImmutableViewportMetrics setViewportSize(int width, int height) {
+        if (width == viewportRectWidth && height == viewportRectHeight) {
+            return this;
+        }
+
+        return new ImmutableViewportMetrics(
+            pageRectLeft, pageRectTop, pageRectRight, pageRectBottom,
+            cssPageRectLeft, cssPageRectTop, cssPageRectRight, cssPageRectBottom,
+            viewportRectLeft, viewportRectTop, width, height,
+            zoomFactor);
+    }
+
+    public ImmutableViewportMetrics setViewportOrigin(float newOriginX, float newOriginY) {
+        return new ImmutableViewportMetrics(
+            pageRectLeft, pageRectTop, pageRectRight, pageRectBottom,
+            cssPageRectLeft, cssPageRectTop, cssPageRectRight, cssPageRectBottom,
+            newOriginX, newOriginY, viewportRectWidth, viewportRectHeight,
+            zoomFactor);
+    }
+
+    public ImmutableViewportMetrics setZoomFactor(float newZoomFactor) {
+        return new ImmutableViewportMetrics(
+            pageRectLeft, pageRectTop, pageRectRight, pageRectBottom,
+            cssPageRectLeft, cssPageRectTop, cssPageRectRight, cssPageRectBottom,
+            viewportRectLeft, viewportRectTop, viewportRectWidth, viewportRectHeight,
+            newZoomFactor);
+    }
+
+    public ImmutableViewportMetrics offsetViewportBy(float dx, float dy) {
+        return setViewportOrigin(viewportRectLeft + dx, viewportRectTop + dy);
+    }
+
+    public ImmutableViewportMetrics offsetViewportByAndClamp(float dx, float dy) {
+        return setViewportOrigin(
+            Math.max(pageRectLeft, Math.min(viewportRectLeft + dx, pageRectRight - getWidth())),
+            Math.max(pageRectTop, Math.min(viewportRectTop + dy, pageRectBottom - getHeight())));
+    }
+
+    public ImmutableViewportMetrics setPageRect(RectF pageRect, RectF cssPageRect) {
+        return new ImmutableViewportMetrics(
+            pageRect.left, pageRect.top, pageRect.right, pageRect.bottom,
+            cssPageRect.left, cssPageRect.top, cssPageRect.right, cssPageRect.bottom,
+            viewportRectLeft, viewportRectTop, viewportRectWidth, viewportRectHeight,
+            zoomFactor);
+    }
+
+    public ImmutableViewportMetrics setPageRectFrom(ImmutableViewportMetrics aMetrics) {
+        if (aMetrics.cssPageRectLeft == cssPageRectLeft &&
+            aMetrics.cssPageRectTop == cssPageRectTop &&
+            aMetrics.cssPageRectRight == cssPageRectRight &&
+            aMetrics.cssPageRectBottom == cssPageRectBottom) {
+            return this;
+        }
+        RectF css = aMetrics.getCssPageRect();
+        return setPageRect(RectUtils.scale(css, zoomFactor), css);
+    }
+
+    /* This will set the zoom factor and re-scale page-size and viewport offset
+     * accordingly. The given focus will remain at the same point on the screen
+     * after scaling.
+     */
+    public ImmutableViewportMetrics scaleTo(float newZoomFactor, PointF focus) {
+        // cssPageRect* is invariant, since we're setting the scale factor
+        // here. The page rect is based on the CSS page rect.
+        float newPageRectLeft = cssPageRectLeft * newZoomFactor;
+        float newPageRectTop = cssPageRectTop * newZoomFactor;
+        float newPageRectRight = cssPageRectLeft + ((cssPageRectRight - cssPageRectLeft) * newZoomFactor);
+        float newPageRectBottom = cssPageRectTop + ((cssPageRectBottom - cssPageRectTop) * newZoomFactor);
+
+        PointF origin = getOrigin();
+        origin.offset(focus.x, focus.y);
+        origin = PointUtils.scale(origin, newZoomFactor / zoomFactor);
+        origin.offset(-focus.x, -focus.y);
+
+        return new ImmutableViewportMetrics(
+            newPageRectLeft, newPageRectTop, newPageRectRight, newPageRectBottom,
+            cssPageRectLeft, cssPageRectTop, cssPageRectRight, cssPageRectBottom,
+            origin.x, origin.y, viewportRectWidth, viewportRectHeight,
+            newZoomFactor);
+    }
+
+    /** Clamps the viewport to remain within the page rect. */
+    public ImmutableViewportMetrics clamp() {
+        RectF newViewport = getViewport();
+
+        // The viewport bounds ought to never exceed the page bounds.
+        if (newViewport.right > pageRectRight)
+            newViewport.offset((pageRectRight) - newViewport.right, 0);
+        if (newViewport.left < pageRectLeft)
+            newViewport.offset(pageRectLeft - newViewport.left, 0);
+
+        if (newViewport.bottom > pageRectBottom)
+            newViewport.offset(0, (pageRectBottom) - newViewport.bottom);
+        if (newViewport.top < pageRectTop)
+            newViewport.offset(0, pageRectTop - newViewport.top);
+
+        // Note that since newViewport is only translated around, the viewport's
+        // width and height are unchanged.
+        return new ImmutableViewportMetrics(
+            pageRectLeft, pageRectTop, pageRectRight, pageRectBottom,
+            cssPageRectLeft, cssPageRectTop, cssPageRectRight, cssPageRectBottom,
+            newViewport.left, newViewport.top, viewportRectWidth, viewportRectHeight,
+            zoomFactor);
+    }
+
+    public boolean fuzzyEquals(ImmutableViewportMetrics other) {
+        // Don't bother checking the pageRectXXX values because they are a product
+        // of the cssPageRectXXX values and the zoomFactor, except with more rounding
+        // error. Checking those is both inefficient and can lead to false negatives.
+        return FloatUtils.fuzzyEquals(cssPageRectLeft, other.cssPageRectLeft)
+            && FloatUtils.fuzzyEquals(cssPageRectTop, other.cssPageRectTop)
+            && FloatUtils.fuzzyEquals(cssPageRectRight, other.cssPageRectRight)
+            && FloatUtils.fuzzyEquals(cssPageRectBottom, other.cssPageRectBottom)
+            && FloatUtils.fuzzyEquals(viewportRectLeft, other.viewportRectLeft)
+            && FloatUtils.fuzzyEquals(viewportRectTop, other.viewportRectTop)
+            && viewportRectWidth == other.viewportRectWidth
+            && viewportRectHeight == other.viewportRectHeight
+            && FloatUtils.fuzzyEquals(zoomFactor, other.zoomFactor);
+    }
+
+    @Override
+    public String toString() {
+        return "ImmutableViewportMetrics v=(" + viewportRectLeft + "," + viewportRectTop + ","
+                + viewportRectWidth + "x" + viewportRectHeight + ") p=(" + pageRectLeft + ","
+                + pageRectTop + "," + pageRectRight + "," + pageRectBottom + ") c=("
+                + cssPageRectLeft + "," + cssPageRectTop + "," + cssPageRectRight + ","
+                + cssPageRectBottom + ") z=" + zoomFactor;
+    }
+}