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author | Allan Sandfeld Jensen <allan.jensen@qt.io> | 2020-10-12 14:27:29 +0200 |
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committer | Allan Sandfeld Jensen <allan.jensen@qt.io> | 2020-10-13 09:35:20 +0000 |
commit | c30a6232df03e1efbd9f3b226777b07e087a1122 (patch) | |
tree | e992f45784689f373bcc38d1b79a239ebe17ee23 /chromium/cc/input/scroll_utils.cc | |
parent | 7b5b123ac58f58ffde0f4f6e488bcd09aa4decd3 (diff) | |
download | qtwebengine-chromium-85-based.tar.gz |
BASELINE: Update Chromium to 85.0.4183.14085-based
Change-Id: Iaa42f4680837c57725b1344f108c0196741f6057
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
Diffstat (limited to 'chromium/cc/input/scroll_utils.cc')
-rw-r--r-- | chromium/cc/input/scroll_utils.cc | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/chromium/cc/input/scroll_utils.cc b/chromium/cc/input/scroll_utils.cc new file mode 100644 index 00000000000..e9c036e3896 --- /dev/null +++ b/chromium/cc/input/scroll_utils.cc @@ -0,0 +1,45 @@ +// Copyright 2020 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 "cc/input/scroll_utils.h" + +#include "base/numerics/ranges.h" +#include "ui/gfx/geometry/size_f.h" +#include "ui/gfx/geometry/vector2d_f.h" + +namespace cc { + +// static +gfx::Vector2dF ScrollUtils::ResolveScrollPercentageToPixels( + const gfx::Vector2dF& delta, + const gfx::SizeF& scroller, + const gfx::SizeF& viewport) { + // Work with unsigned values and keep sign information in sign_x / sign_y. + float sign_x = std::signbit(delta.x()) ? -1 : 1; + float sign_y = std::signbit(delta.y()) ? -1 : 1; + float delta_x = std::abs(delta.x()); + float delta_y = std::abs(delta.y()); + + // Resolved deltas in percent based scrolling are clamped at min by 16 pixels. + float min = kMinPixelDeltaForPercentBasedScroll; + + // Resolve and clamp horizontal scroll + if (delta_x > 0) { + delta_x = delta_x * std::min(scroller.width(), viewport.width()); + if (delta_x < min) + delta_x = min; + } + + // Resolve and clamps vertical scroll. + if (delta_y > 0) { + delta_y = delta_y * std::min(scroller.height(), viewport.height()); + if (delta_y < min) + delta_y = min; + } + + return gfx::Vector2dF(std::copysign(delta_x, sign_x), + std::copysign(delta_y, sign_y)); +} + +} // namespace cc |