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+/* 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/. */
+
+#ifndef nsViewportInfo_h___
+#define nsViewportInfo_h___
+
+#include <algorithm>
+#include <stdint.h>
+#include "mozilla/Attributes.h"
+#include "mozilla/StaticPrefs_apz.h"
+#include "Units.h"
+
+namespace mozilla::dom {
+enum class ViewportFitType : uint8_t {
+ Auto,
+ Contain,
+ Cover,
+};
+} // namespace mozilla::dom
+
+/**
+ * Default values for the nsViewportInfo class.
+ */
+static const mozilla::CSSIntSize kViewportMinSize(200, 40);
+static const mozilla::CSSIntSize kViewportMaxSize(10000, 10000);
+
+inline mozilla::LayoutDeviceToScreenScale ViewportMinScale() {
+ return mozilla::LayoutDeviceToScreenScale(
+ std::max(mozilla::StaticPrefs::apz_min_zoom(), 0.1f));
+}
+
+inline mozilla::LayoutDeviceToScreenScale ViewportMaxScale() {
+ return mozilla::LayoutDeviceToScreenScale(
+ std::min(mozilla::StaticPrefs::apz_max_zoom(), 100.0f));
+}
+
+/**
+ * Information retrieved from the <meta name="viewport"> tag. See
+ * Document::GetViewportInfo for more information on this functionality.
+ */
+class MOZ_STACK_CLASS nsViewportInfo {
+ public:
+ enum class AutoSizeFlag {
+ AutoSize,
+ FixedSize,
+ };
+ enum class AutoScaleFlag {
+ AutoScale,
+ FixedScale,
+ };
+ enum class ZoomFlag {
+ AllowZoom,
+ DisallowZoom,
+ };
+ enum class ZoomBehaviour {
+ Mobile,
+ Desktop, // disallows zooming out past default zoom
+ };
+ nsViewportInfo(const mozilla::ScreenIntSize& aDisplaySize,
+ const mozilla::CSSToScreenScale& aDefaultZoom,
+ ZoomFlag aZoomFlag, ZoomBehaviour aBehaviour)
+ : mDefaultZoom(aDefaultZoom),
+ mViewportFit(mozilla::dom::ViewportFitType::Auto),
+ mDefaultZoomValid(true),
+ mAutoSize(true),
+ mAllowZoom(aZoomFlag == ZoomFlag::AllowZoom) {
+ mSize = mozilla::ScreenSize(aDisplaySize) / mDefaultZoom;
+ mozilla::CSSToLayoutDeviceScale pixelRatio(1.0f);
+ if (aBehaviour == ZoomBehaviour::Desktop) {
+ mMinZoom = aDefaultZoom;
+ } else {
+ mMinZoom = pixelRatio * ViewportMinScale();
+ }
+ mMaxZoom = pixelRatio * ViewportMaxScale();
+ ConstrainViewportValues();
+ }
+
+ nsViewportInfo(const mozilla::CSSToScreenScale& aDefaultZoom,
+ const mozilla::CSSToScreenScale& aMinZoom,
+ const mozilla::CSSToScreenScale& aMaxZoom,
+ const mozilla::CSSSize& aSize, AutoSizeFlag aAutoSizeFlag,
+ AutoScaleFlag aAutoScaleFlag, ZoomFlag aZoomFlag,
+ mozilla::dom::ViewportFitType aViewportFit)
+ : mDefaultZoom(aDefaultZoom),
+ mMinZoom(aMinZoom),
+ mMaxZoom(aMaxZoom),
+ mSize(aSize),
+ mViewportFit(aViewportFit),
+ mDefaultZoomValid(aAutoScaleFlag != AutoScaleFlag::AutoScale),
+ mAutoSize(aAutoSizeFlag == AutoSizeFlag::AutoSize),
+ mAllowZoom(aZoomFlag == ZoomFlag::AllowZoom) {
+ ConstrainViewportValues();
+ }
+
+ bool IsDefaultZoomValid() const { return mDefaultZoomValid; }
+ mozilla::CSSToScreenScale GetDefaultZoom() const { return mDefaultZoom; }
+ mozilla::CSSToScreenScale GetMinZoom() const { return mMinZoom; }
+ mozilla::CSSToScreenScale GetMaxZoom() const { return mMaxZoom; }
+
+ mozilla::CSSSize GetSize() const { return mSize; }
+
+ bool IsAutoSizeEnabled() const { return mAutoSize; }
+ bool IsZoomAllowed() const { return mAllowZoom; }
+
+ mozilla::dom::ViewportFitType GetViewportFit() const { return mViewportFit; }
+
+ static constexpr float kAuto = -1.0f;
+ static constexpr float kExtendToZoom = -2.0f;
+ static constexpr float kDeviceSize =
+ -3.0f; // for device-width or device-height
+
+ // MIN/MAX computations where one of the arguments is auto resolve to the
+ // other argument. For instance, MIN(0.25, auto) = 0.25, and
+ // MAX(5, auto) = 5.
+ // https://drafts.csswg.org/css-device-adapt/#constraining-defs
+ static const float& Max(const float& aA, const float& aB);
+ static const float& Min(const float& aA, const float& aB);
+
+ private:
+ /**
+ * Constrain the viewport calculations from the
+ * Document::GetViewportInfo() function in order to always return
+ * sane minimum/maximum values.
+ */
+ void ConstrainViewportValues();
+
+ // Default zoom indicates the level at which the display is 'zoomed in'
+ // initially for the user, upon loading of the page.
+ mozilla::CSSToScreenScale mDefaultZoom;
+
+ // The minimum zoom level permitted by the page.
+ mozilla::CSSToScreenScale mMinZoom;
+
+ // The maximum zoom level permitted by the page.
+ mozilla::CSSToScreenScale mMaxZoom;
+
+ // The size of the viewport, specified by the <meta name="viewport"> tag.
+ mozilla::CSSSize mSize;
+
+ // The value of the viewport-fit.
+ mozilla::dom::ViewportFitType mViewportFit;
+
+ // If the default zoom was specified and was between the min and max
+ // zoom values.
+ // FIXME: Bug 1504362 - Unify this and mDefaultZoom into
+ // Maybe<CSSToScreenScale>.
+ bool mDefaultZoomValid;
+
+ // Whether or not we should automatically size the viewport to the device's
+ // width. This is true if the document has been optimized for mobile, and
+ // the width property of a specified <meta name="viewport"> tag is either
+ // not specified, or is set to the special value 'device-width'.
+ bool mAutoSize;
+
+ // Whether or not the user can zoom in and out on the page. Default is true.
+ bool mAllowZoom;
+};
+
+#endif