1 files changed, 262 insertions, 0 deletions
diff --git a/gfx/src/nsITheme.h b/gfx/src/nsITheme.h
new file mode 100644
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+++ b/gfx/src/nsITheme.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+/* service providing platform-specific native rendering for widgets */
+
+#ifndef nsITheme_h_
+#define nsITheme_h_
+
+#include "mozilla/AlreadyAddRefed.h"
+#include "nsISupports.h"
+#include "nsID.h"
+#include "nscore.h"
+#include "Units.h"
+
+struct nsRect;
+class gfxContext;
+class nsAttrValue;
+class nsPresContext;
+class nsDeviceContext;
+class nsIFrame;
+class nsAtom;
+class nsIWidget;
+
+namespace mozilla {
+class ComputedStyle;
+enum class StyleAppearance : uint8_t;
+enum class StyleScrollbarWidth : uint8_t;
+namespace layers {
+class StackingContextHelper;
+class RenderRootStateManager;
+}  // namespace layers
+namespace widget {
+class Theme;
+}  // namespace widget
+namespace wr {
+class DisplayListBuilder;
+class IpcResourceUpdateQueue;
+}  // namespace wr
+}  // namespace mozilla
+
+// IID for the nsITheme interface
+// {7329f760-08cb-450f-8225-dae729096dec}
+#define NS_ITHEME_IID                                \
+  {                                                  \
+    0x7329f760, 0x08cb, 0x450f, {                    \
+      0x82, 0x25, 0xda, 0xe7, 0x29, 0x09, 0x6d, 0xec \
+    }                                                \
+  }
+
+/**
+ * nsITheme is a service that provides platform-specific native
+ * rendering for widgets.  In other words, it provides the necessary
+ * operations to draw a rendering object (an nsIFrame) as a native
+ * widget.
+ *
+ * All the methods on nsITheme take a rendering context or device
+ * context, a frame (the rendering object), and a widget type (one of
+ * the constants in nsThemeConstants.h).
+ */
+class nsITheme : public nsISupports {
+ protected:
+  using LayoutDeviceIntMargin = mozilla::LayoutDeviceIntMargin;
+  using LayoutDeviceIntSize = mozilla::LayoutDeviceIntSize;
+  using LayoutDeviceIntCoord = mozilla::LayoutDeviceIntCoord;
+  using StyleAppearance = mozilla::StyleAppearance;
+  using StyleScrollbarWidth = mozilla::StyleScrollbarWidth;
+  using ComputedStyle = mozilla::ComputedStyle;
+
+ public:
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_ITHEME_IID)
+
+  /**
+   * Draw the actual theme background.
+   * @param aContext the context to draw into
+   * @param aFrame the frame for the widget that we're drawing
+   * @param aWidgetType the -moz-appearance value to draw
+   * @param aRect the rectangle defining the area occupied by the widget
+   * @param aDirtyRect the rectangle that needs to be drawn
+   * @param DrawOverflow whether outlines, shadows and other such overflowing
+   *        things should be drawn. Honoring this creates better results for
+   *        box-shadow, though it's not a hard requirement.
+   */
+  enum class DrawOverflow { No, Yes };
+  NS_IMETHOD DrawWidgetBackground(gfxContext* aContext, nsIFrame* aFrame,
+                                  StyleAppearance aWidgetType,
+                                  const nsRect& aRect, const nsRect& aDirtyRect,
+                                  DrawOverflow = DrawOverflow::Yes) = 0;
+
+  /**
+   * Create WebRender commands for the theme background.
+   * @return true if the theme knows how to create WebRender commands for the
+   *         given widget type, false if DrawWidgetBackground need sto be called
+   *         instead.
+   */
+  virtual bool CreateWebRenderCommandsForWidget(
+      mozilla::wr::DisplayListBuilder& aBuilder,
+      mozilla::wr::IpcResourceUpdateQueue& aResources,
+      const mozilla::layers::StackingContextHelper& aSc,
+      mozilla::layers::RenderRootStateManager* aManager, nsIFrame* aFrame,
+      StyleAppearance aWidgetType, const nsRect& aRect) {
+    return false;
+  }
+
+  /**
+   * Returns the minimum widths of a scrollbar for a given style, that is, the
+   * minimum width for a vertical scrollbar, and the minimum height of a
+   * horizontal scrollbar.
+   */
+  enum class Overlay { No, Yes };
+  virtual LayoutDeviceIntCoord GetScrollbarSize(const nsPresContext*,
+                                                StyleScrollbarWidth,
+                                                Overlay) = 0;
+
+  /**
+   * Return the border for the widget, in device pixels.
+   */
+  [[nodiscard]] virtual LayoutDeviceIntMargin GetWidgetBorder(
+      nsDeviceContext* aContext, nsIFrame* aFrame,
+      StyleAppearance aWidgetType) = 0;
+
+  /**
+   * This method can return false to indicate that the CSS padding
+   * value should be used.  Otherwise, it will fill in aResult with the
+   * computed padding, in pixels, and return true.
+   *
+   * XXXldb This ought to be required to return true for non-containers
+   * so that we don't let specified padding that has no effect change
+   * the computed padding and potentially the size.
+   */
+  virtual bool GetWidgetPadding(nsDeviceContext* aContext, nsIFrame* aFrame,
+                                StyleAppearance aWidgetType,
+                                LayoutDeviceIntMargin* aResult) = 0;
+
+  /**
+   * On entry, *aResult is positioned at 0,0 and sized to the new size
+   * of aFrame (aFrame->GetSize() may be stale and should not be used).
+   * This method can return false to indicate that no special
+   * overflow area is required by the native widget. Otherwise it will
+   * fill in aResult with the desired overflow area, in appunits, relative
+   * to the frame origin, and return true.
+   *
+   * This overflow area is used to determine what area needs to be
+   * repainted when the widget changes.  However, it does not affect the
+   * widget's size or what area is reachable by scrollbars.  (In other
+   * words, in layout terms, it affects ink overflow but not
+   * scrollable overflow.)
+   */
+  virtual bool GetWidgetOverflow(nsDeviceContext* aContext, nsIFrame* aFrame,
+                                 StyleAppearance aWidgetType,
+                                 /*INOUT*/ nsRect* aOverflowRect) {
+    return false;
+  }
+
+  /**
+   * Get the preferred content-box size of a checkbox / radio button, in app
+   * units.  Historically 9px.
+   */
+  virtual nscoord GetCheckboxRadioPrefSize() {
+    return mozilla::CSSPixel::ToAppUnits(9);
+  }
+
+  /**
+   * Get the minimum border-box size of a widget, in device pixels.
+   */
+  virtual mozilla::LayoutDeviceIntSize GetMinimumWidgetSize(
+      nsPresContext* aPresContext, nsIFrame* aFrame,
+      StyleAppearance aWidgetType) = 0;
+
+  enum Transparency { eOpaque = 0, eTransparent, eUnknownTransparency };
+
+  /**
+   * Returns what we know about the transparency of the widget.
+   */
+  virtual Transparency GetWidgetTransparency(nsIFrame* aFrame,
+                                             StyleAppearance aWidgetType) {
+    return eUnknownTransparency;
+  }
+
+  /**
+   * Sets |*aShouldRepaint| to indicate whether an attribute or content state
+   * change should trigger a repaint.  Call with null |aAttribute| (and
+   * null |aOldValue|) for content state changes.
+   */
+  NS_IMETHOD WidgetStateChanged(nsIFrame* aFrame, StyleAppearance aWidgetType,
+                                nsAtom* aAttribute, bool* aShouldRepaint,
+                                const nsAttrValue* aOldValue) = 0;
+
+  NS_IMETHOD ThemeChanged() = 0;
+
+  virtual bool WidgetAppearanceDependsOnWindowFocus(
+      StyleAppearance aWidgetType) {
+    return false;
+  }
+
+  /**
+   * ThemeGeometryType values are used for describing themed nsIFrames in
+   * calls to nsIWidget::UpdateThemeGeometries. We don't simply pass the
+   * -moz-appearance value ("widget type") of the frame because the widget may
+   * want to treat different frames with the same -moz-appearance differently
+   * based on other properties of the frame. So we give the theme a first look
+   * at the frame in nsITheme::ThemeGeometryTypeForWidget and pass the
+   * returned ThemeGeometryType along to the widget.
+   * Each theme backend defines the ThemeGeometryType values it needs in its
+   * own nsITheme subclass. eThemeGeometryTypeUnknown is the only value that's
+   * shared between backends.
+   */
+  typedef uint8_t ThemeGeometryType;
+  enum { eThemeGeometryTypeUnknown = 0 };
+
+  /**
+   * Returns the theme geometry type that should be used in the ThemeGeometry
+   * array that's passed to the widget using nsIWidget::UpdateThemeGeometries.
+   * A return value of eThemeGeometryTypeUnknown means that this frame will
+   * not be included in the ThemeGeometry array.
+   */
+  virtual ThemeGeometryType ThemeGeometryTypeForWidget(
+      nsIFrame* aFrame, StyleAppearance aWidgetType) {
+    return eThemeGeometryTypeUnknown;
+  }
+
+  /**
+   * Can the nsITheme implementation handle this widget?
+   */
+  virtual bool ThemeSupportsWidget(nsPresContext* aPresContext,
+                                   nsIFrame* aFrame,
+                                   StyleAppearance aWidgetType) = 0;
+
+  virtual bool WidgetIsContainer(StyleAppearance aWidgetType) = 0;
+
+  /**
+   * Does the nsITheme implementation draw its own focus ring for this widget?
+   */
+  virtual bool ThemeDrawsFocusForWidget(nsIFrame*, StyleAppearance) = 0;
+
+  // Whether we want an inner focus ring for buttons and menulists.
+  virtual bool ThemeWantsButtonInnerFocusRing() { return false; }
+
+  /**
+   * Should we insert a dropmarker inside of combobox button?
+   */
+  virtual bool ThemeNeedsComboboxDropmarker() = 0;
+
+  virtual bool ThemeSupportsScrollbarButtons() = 0;
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsITheme, NS_ITHEME_IID)
+
+// Singleton accessor functions, these should never return null.
+//
+// Do not use directly, use nsPresContext::Theme instead.
+extern already_AddRefed<nsITheme> do_GetNativeThemeDoNotUseDirectly();
+extern already_AddRefed<nsITheme> do_GetBasicNativeThemeDoNotUseDirectly();
+extern already_AddRefed<nsITheme> do_GetRDMThemeDoNotUseDirectly();
+
+// Native theme creation function, these should never return null.
+extern already_AddRefed<mozilla::widget::Theme>
+do_CreateNativeThemeDoNotUseDirectly();
+
+#endif