layout/generic/nsPageFrame.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6 #ifndef nsPageFrame_h___
   7 #define nsPageFrame_h___
   8
   9 #include "mozilla/Attributes.h"
  10 #include "nsContainerFrame.h"
  11 #include "nsLeafFrame.h"
  12
  13 class nsFontMetrics;
  14 class nsPageContentFrame;
  15 class nsSharedPageData;
  16
  17 namespace mozilla {
  18 class PresShell;
  19 }  // namespace mozilla
  20
  21 // Page frame class. Represents an individual page, in paginated mode.
  22 class nsPageFrame final : public nsContainerFrame {
  23  public:
  24   NS_DECL_QUERYFRAME
  25   NS_DECL_FRAMEARENA_HELPERS(nsPageFrame)
  26
  27   friend nsPageFrame* NS_NewPageFrame(mozilla::PresShell* aPresShell,
  28                                       ComputedStyle* aStyle);
  29
  30   void Reflow(nsPresContext* aPresContext, ReflowOutput& aReflowOutput,
  31               const ReflowInput& aReflowInput,
  32               nsReflowStatus& aStatus) override;
  33
  34   void BuildDisplayList(nsDisplayListBuilder* aBuilder,
  35                         const nsDisplayListSet& aLists) override;
  36
  37 #ifdef DEBUG_FRAME_DUMP
  38   nsresult GetFrameName(nsAString& aResult) const override;
  39 #endif
  40
  41   //////////////////
  42   // For Printing
  43   //////////////////
  44
  45   // Determine this page's page-number, based on its previous continuation
  46   // (whose page number is presumed to already be known).
  47   void DeterminePageNum();
  48   int32_t GetPageNum() const { return mPageNum; }
  49
  50   void SetSharedPageData(nsSharedPageData* aPD);
  51   nsSharedPageData* GetSharedPageData() const { return mPD; }
  52
  53   void PaintHeaderFooter(gfxContext& aRenderingContext, nsPoint aPt,
  54                          bool aSubpixelAA);
  55
  56   const nsMargin& GetUsedPageContentMargin() const {
  57     return mPageContentMargin;
  58   }
  59
  60   uint32_t IndexOnSheet() const { return mIndexOnSheet; }
  61   void SetIndexOnSheet(uint32_t aIndexOnSheet) {
  62     mIndexOnSheet = aIndexOnSheet;
  63   }
  64
  65   ComputeTransformFunction GetTransformGetter() const override;
  66
  67   nsPageContentFrame* PageContentFrame() const;
  68
  69   nsSize ComputePageSize() const;
  70
  71   // Computes the scaling factor to fit the page to the sheet in the single
  72   // page-per-sheet case. (The multiple pages-per-sheet case is currently
  73   // different - see the comment for
  74   // PrintedSheetFrame::ComputePagesPerSheetGridMetrics and code in
  75   // ComputePagesPerSheetAndPageSizeTransform.) The page and sheet dimensions
  76   // may be different due to a CSS page-size that gives the page a size that is
  77   // too large to fit on the sheet that we are printing to.
  78   float ComputeSinglePPSPageSizeScale(const nsSize aContentPageSize) const;
  79
  80   // Returns the rotation from CSS `page-orientation` property, if set, and if
  81   // it applies. Note: the single page-per-sheet case is special since in that
  82   // case we effectively rotate the sheet (as opposed to rotating pages in
  83   // their pages-per-sheet grid cell). In this case we return zero if the
  84   // output medium does not support changing the dimensions (orientation) of
  85   // the sheet (i.e. only print preview and save-to-PDF are supported).
  86   double GetPageOrientationRotation(nsSharedPageData* aPD) const;
  87
  88   // The default implementation of FirstContinuation in nsSplittableFrame is
  89   // implemented in linear time, walking back through the linked list of
  90   // continuations via mPrevContinuation.
  91   // For nsPageFrames, we can find the first continuation through the frame
  92   // tree structure in constant time.
  93   nsIFrame* FirstContinuation() const final;
  94
  95  protected:
  96   explicit nsPageFrame(ComputedStyle* aStyle, nsPresContext* aPresContext);
  97   virtual ~nsPageFrame();
  98
  99   typedef enum { eHeader, eFooter } nsHeaderFooterEnum;
 100
 101   nscoord GetXPosition(gfxContext& aRenderingContext,
 102                        nsFontMetrics& aFontMetrics, const nsRect& aRect,
 103                        int32_t aJust, const nsString& aStr);
 104
 105   nsReflowStatus ReflowPageContent(nsPresContext*,
 106                                    const ReflowInput& aPageReflowInput);
 107
 108   void DrawHeaderFooter(gfxContext& aRenderingContext,
 109                         nsFontMetrics& aFontMetrics,
 110                         nsHeaderFooterEnum aHeaderFooter, int32_t aJust,
 111                         const nsString& sStr, const nsRect& aRect,
 112                         nscoord aHeight, nscoord aAscent, nscoord aWidth);
 113
 114   void DrawHeaderFooter(gfxContext& aRenderingContext,
 115                         nsFontMetrics& aFontMetrics,
 116                         nsHeaderFooterEnum aHeaderFooter,
 117                         const nsString& aStrLeft, const nsString& aStrRight,
 118                         const nsString& aStrCenter, const nsRect& aRect,
 119                         nscoord aAscent, nscoord aHeight);
 120
 121   void ProcessSpecialCodes(const nsString& aStr, nsString& aNewStr);
 122
 123   static constexpr int32_t kPageNumUnset = -1;
 124   // 1-based page-num
 125   int32_t mPageNum = kPageNumUnset;
 126
 127   // 0-based index on the sheet that we belong to. Unused/meaningless if this
 128   // page has frame state bit NS_PAGE_SKIPPED_BY_CUSTOM_RANGE.
 129   uint32_t mIndexOnSheet = 0;
 130
 131   // Note: this will be set before reflow, and it's strongly owned by our
 132   // nsPageSequenceFrame, which outlives us.
 133   nsSharedPageData* mPD = nullptr;
 134
 135   // Computed page content margins.
 136   //
 137   // This is the amount of space from the edges of the content to the edges,
 138   // measured in the content coordinate space. This is as opposed to the
 139   // coordinate space of the physical paper. This might be different due to
 140   // a CSS page-size that is too large to fit on the paper, causing content to
 141   // be scaled to fit.
 142   //
 143   // These margins take into account:
 144   //    * CSS-defined margins (content units)
 145   //    * User-supplied margins (physical units)
 146   //    * Unwriteable-supplied margins (physical units)
 147   //
 148   // When computing these margins, all physical units have the inverse of the
 149   // scaling factor caused by CSS page-size downscaling applied. This ensures
 150   // that even if the content will be downscaled, it will respect the (now
 151   // upscaled) physical unwriteable margins required by the printer.
 152   // For user-supplied margins, it isn't immediately obvious to the user what
 153   // the intended page-size of the document is, so we consider these margins to
 154   // be in the physical space of the paper.
 155   nsMargin mPageContentMargin;
 156 };
 157
 158 class nsPageBreakFrame final : public nsLeafFrame {
 159   NS_DECL_FRAMEARENA_HELPERS(nsPageBreakFrame)
 160
 161   explicit nsPageBreakFrame(ComputedStyle* aStyle, nsPresContext* aPresContext);
 162   ~nsPageBreakFrame();
 163
 164   void Reflow(nsPresContext* aPresContext, ReflowOutput& aReflowOutput,
 165               const ReflowInput& aReflowInput,
 166               nsReflowStatus& aStatus) override;
 167
 168 #ifdef DEBUG_FRAME_DUMP
 169   nsresult GetFrameName(nsAString& aResult) const override;
 170 #endif
 171
 172  protected:
 173   nscoord GetIntrinsicISize() override;
 174   nscoord GetIntrinsicBSize() override;
 175
 176   friend nsIFrame* NS_NewPageBreakFrame(mozilla::PresShell* aPresShell,
 177                                         ComputedStyle* aStyle);
 178 };
 179
 180 #endif /* nsPageFrame_h___ */