ui: Add methods to clamp Sizes, Points, and Vectors from above or below.

cc/page_scale_animation.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 
 #include "cc/page_scale_animation.h"
+
+#include "cc/geometry.h"
 #include "ui/gfx/point_f.h"
 #include "ui/gfx/rect_f.h"
 
-#include <algorithm>
 #include <math.h>
 
 namespace {
 
 gfx::PointF toPointF(const gfx::Vector2dF& vector)
 {
     return gfx::PointF(vector.x(), vector.y());
 }
 
 // This takes a viewport-relative vector and returns a vector whose values are
@@ skipping 109 matching lines @@
     // where both anchor{x,y} and normalized{x,y} begin as unknowns. Solving
     // for the normalized, we get the following formulas:
     gfx::Vector2dF normalized;
     normalized.set_x((startRect.x() - targetRect.x()) / (targetRect.width() - startRect.width()));
     normalized.set_y((startRect.y() - targetRect.y()) / (targetRect.height() - startRect.height()));
     m_targetAnchor = m_targetScrollOffset + denormalizeToViewport(normalized, viewportSizeAtScale(m_targetPageScaleFactor));
 }
 
 void PageScaleAnimation::clampTargetScrollOffset()
 {
-    gfx::Vector2dF maxScrollPosition;
-    maxScrollPosition.set_x(m_rootLayerSize.width() - viewportSizeAtScale(m_targetPageScaleFactor).width());
-    maxScrollPosition.set_y(m_rootLayerSize.height() - viewportSizeAtScale(m_targetPageScaleFactor).height());
-    m_targetScrollOffset.set_x(std::max<float>(0, m_targetScrollOffset.x()));
-    m_targetScrollOffset.set_y(std::max<float>(0, m_targetScrollOffset.y()));
-    m_targetScrollOffset.set_x(std::min<float>(maxScrollPosition.x(), m_targetScrollOffset.x()));
-    m_targetScrollOffset.set_y(std::min<float>(maxScrollPosition.y(), m_targetScrollOffset.y()));
+    gfx::Vector2dF maxScrollOffset = BottomRight(gfx::RectF(m_rootLayerSize)) - BottomRight(gfx::RectF(viewportSizeAtScale(m_targetPageScaleFactor)));
+    m_targetScrollOffset.ClampToMin(gfx::Vector2dF());
+    m_targetScrollOffset.ClampToMax(maxScrollOffset);
 }
 
 gfx::Vector2dF PageScaleAnimation::scrollOffsetAtTime(double time) const
 {
     return scrollOffsetAt(interpAtTime(time));
 }
 
 float PageScaleAnimation::pageScaleFactorAtTime(double time) const
 {
     return pageScaleFactorAt(interpAtTime(time));
@@ skipping 54 matching lines @@
 
     // Linearly interpolate the magnitude in log scale.
     float diff = m_targetPageScaleFactor / m_startPageScaleFactor;
     float logDiff = log(diff);
     logDiff *= interp;
     diff = exp(logDiff);
     return m_startPageScaleFactor * diff;
 }
 
 }  // namespace cc