Added Header and Footer support using Skia

chrome/renderer/print_web_view_helper.h

Index: chrome/renderer/print_web_view_helper.h
diff --git a/chrome/renderer/print_web_view_helper.h b/chrome/renderer/print_web_view_helper.h
index ba0d9e51e314794fb2587b3502c0aae76441a744..012c7587a1fb802a6a1047888130e7b1f98f21f5 100644
--- a/chrome/renderer/print_web_view_helper.h
+++ b/chrome/renderer/print_web_view_helper.h
@@ -9,9 +9,15 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/shared_memory.h"
 #include "base/time.h"
+#include "base/utf_string_conversions.h"
+#include "base/values.h"
 #include "content/renderer/render_view_observer.h"
 #include "content/renderer/render_view_observer_tracker.h"
 #include "printing/metafile.h"
+#include "skia/ext/vector_canvas.h"
+#include "third_party/skia/include/core/SkPaint.h"
+#include "third_party/skia/include/core/SkRefCnt.h"
+#include "third_party/skia/include/core/SkScalar.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebFrameClient.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebViewClient.h"
 #include "ui/gfx/size.h"
@@ -107,7 +113,11 @@ class PrintWebViewHelper : public RenderViewObserver,
   void OnInitiatePrintPreview();
 
   // Generate a print preview using |settings|.
-  void OnPrintPreview(const DictionaryValue& settings);
+  // |header_footer_info| contains the necessary strings generated by the
+  // browser process to be printed as headers and footers if requested by the
+  // user.
+  void OnPrintPreview(const DictionaryValue& settings,
+      const DictionaryValue& header_footer_info);

[kmadhusu, 2011/07/13 18:47:53]

nit: Fix indentation.

[Aayush Kumar, 2011/07/13 21:52:16]

Done.

 
   // Print / preview the node under the context menu.
   void OnPrintNodeUnderContextMenu();
@@ -165,7 +175,9 @@ class PrintWebViewHelper : public RenderViewObserver,
   void PrintPageInternal(const PrintMsg_PrintPage_Params& params,
                          const gfx::Size& canvas_size,
                          WebKit::WebFrame* frame,
-                         printing::Metafile* metafile);
+                         printing::Metafile* metafile,
+                         bool is_preview,
+                         int total_pages);
 #else
   void PrintPageInternal(const PrintMsg_PrintPage_Params& params,
                          const gfx::Size& canvas_size,
@@ -283,6 +295,61 @@ class PrintWebViewHelper : public RenderViewObserver,
   int preview_page_count_;
   scoped_ptr<PrintMsg_PrintPages_Params> old_print_pages_params_;
 
+  // Contains strings generated by the browser process to be printed as headers
+  // and footers if requested by the user.
+  const DictionaryValue* header_footer_info_;
+
+  // Specifies the horizontal alignment of the Headers and Footers.
+  enum HorizontalHeaderFooterPosition {

[kmadhusu, 2011/07/13 18:47:53]

Move these enums to print_job_constants.h &.cc and the new functions to an
unnamed namespace. 

+    LEFT,
+    CENTER,
+    RIGHT
+  };
+
+  // Specifies the vertical alignment of the Headers and Footers.
+  enum VerticalHeaderFooterPosition {
+    TOP,
+    BOTTOM
+  };
+
+  // Gets the x-coordinate from where we want to start printing the current text
+  // depending on the alignment (LEFT, RIGHT, CENTER).
+  SkScalar GetHorizontalCoordinate(
+    string16 text,
+    SkPaint paint,
+    HorizontalHeaderFooterPosition pos,
+    SkScalar margin_left_in_points,
+    SkScalar margin_right_in_points,
+    SkScalar content_width_in_points);
+
+  // Gets the y-coordinate from where we want to start printing based on if we
+  // are printing the Header or the Footer (TOP or BOTTOM).
+  SkScalar GetVerticalCoordinate(
+    SkPaint paint,
+    VerticalHeaderFooterPosition pos,
+    SkScalar margin_left_in_points,
+    SkScalar margin_right_in_points,
+    SkScalar content_height_in_points);
+
+  // Interstice or gap between different Header and Footer components.
+  // Hardcoded to 0.25cm = 1/10" = 7.2 points
+  const SkScalar header_footer_interstice;
+
+  // Given a text, the positions and the paint object, this method calculates
+  // the coordinates and prints the text at those co-ordinates.
+  void PrintHeaderFooterText(
+      string16 text,
+      SkPaint paint,
+      const SkRefPtr<skia::VectorCanvas>& canvas,
+      SkScalar margin_left_in_points,

[Lei Zhang, 2011/07/12 22:04:50]

Consider using some additional data structures. When your method has 12 methods,
it's getting pretty ugly.

[Aayush Kumar, 2011/07/13 21:52:16]

Now private variables in PrintWebViewHelper class
On 2011/07/12 22:04:50, Lei Zhang wrote:

+      SkScalar margin_right_in_points,
+      SkScalar content_width_in_points,
+      SkScalar margin_top_in_points,
+      SkScalar margin_bottom_in_points,
+      SkScalar content_height_in_points,
+      HorizontalHeaderFooterPosition hor_pos,
+      VerticalHeaderFooterPosition ver_pos);
+
   DISALLOW_COPY_AND_ASSIGN(PrintWebViewHelper);
 };