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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.h | |
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.h')
-rw-r--r-- | chromium/cc/input/scroll_utils.h | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/chromium/cc/input/scroll_utils.h b/chromium/cc/input/scroll_utils.h new file mode 100644 index 00000000000..34fb3be7773 --- /dev/null +++ b/chromium/cc/input/scroll_utils.h @@ -0,0 +1,43 @@ +// 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. + +#ifndef CC_INPUT_SCROLL_UTILS_H_ +#define CC_INPUT_SCROLL_UTILS_H_ + +#include "cc/cc_export.h" + +namespace gfx { +class Vector2dF; +class SizeF; +} // namespace gfx + +namespace cc { + +static constexpr int kPixelsPerLineStep = 40; +static constexpr float kMinFractionToStepWhenPaging = 0.875f; + +// Each directional scroll for percentage-based units should scroll 1/8th of +// the scrollable area. +static constexpr float kPercentDeltaForDirectionalScroll = 0.125f; + +// Scroll deltas are lower-bounded by 16 physical pixels in percent-based +// scrolls. +static constexpr float kMinPixelDeltaForPercentBasedScroll = 16; + +// Class for scroll helper methods in cc and blink. +class CC_EXPORT ScrollUtils { + public: + // Transforms a |scroll_delta| in percent units to pixel units based in its + // |scroller_size|. Clamps it by 16 pixels to avoid too small deltas for tiny + // scrollers and 12.5% of |viewport_size| to avoid too large deltas. + // Inputs and output muest be in physical pixels. + static gfx::Vector2dF ResolveScrollPercentageToPixels( + const gfx::Vector2dF& scroll_delta, + const gfx::SizeF& scroller_size, + const gfx::SizeF& viewport_size); +}; + +} // namespace cc + +#endif // CC_INPUT_SCROLL_UTILS_H_ |