Added Header and Footer support using Skia

chrome/renderer/print_web_view_helper.cc

Index: chrome/renderer/print_web_view_helper.cc
diff --git a/chrome/renderer/print_web_view_helper.cc b/chrome/renderer/print_web_view_helper.cc
index 36a67c407cee2e3390b8aa1d425454df4e85fd14..81114a22f4af7361d00745b746e86f537342f679 100644
--- a/chrome/renderer/print_web_view_helper.cc
+++ b/chrome/renderer/print_web_view_helper.cc
@@ -4,12 +4,17 @@
 
 #include "chrome/renderer/print_web_view_helper.h"
 
+#include <algorithm>
+#include <cmath>
 #include <string>
 
 #include "base/command_line.h"
+#include "base/i18n/time_formatting.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/process_util.h"
+#include "base/string_number_conversions.h"
+#include "base/time.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/print_messages.h"
@@ -32,13 +37,22 @@
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebURLResponse.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebView.h"
 #include "ui/base/l10n/l10n_util.h"
+#include "ui/base/text/text_elider.h"

[kmadhusu, 2011/07/26 20:27:50]

can this header file go inside the #if defined(USE_SKIA) block?

[Aayush Kumar, 2011/07/28 17:28:41]

This is not skia specific and it will be used by CoreGraphics as well.  However,
I've put all these header files inside the #if defined (USE_SKIA) block for the
time being. 
On 2011/07/26 20:27:50, kmadhusu wrote:

 
 #if defined(OS_POSIX)
 #include "content/common/view_messages.h"
 #endif
 
+#if defined(USE_SKIA)
+#include "skia/ext/vector_canvas.h"
+#include "skia/ext/vector_platform_device_skia.h"
+#include "third_party/skia/include/core/SkTypeface.h"
+#endif
+
+using base::Time;
 using printing::ConvertPixelsToPoint;
 using printing::ConvertPixelsToPointDouble;
+using printing::ConvertPointsToPixelDouble;
 using printing::ConvertUnit;
 using printing::ConvertUnitDouble;
 using WebKit::WebConsoleMessage;
@@ -88,12 +102,215 @@ bool PrintMsg_Print_Params_IsEqual(
          oldParams.params.supports_alpha_blend ==
              newParams.params.supports_alpha_blend &&
          oldParams.pages.size() == newParams.pages.size() &&
+         oldParams.params.display_header_footer ==
+             newParams.params.display_header_footer &&
          std::equal(oldParams.pages.begin(), oldParams.pages.end(),
              newParams.pages.begin());
 }
 
+#if defined(USE_SKIA)
+// Splits the horizontal width equally into segments with an interstice
+// between each segment. Returns the width of this segment.
+SkScalar GetSegmentWidth(const PageSizeMargins& page_layout) {
+  // Interstice is left at both ends of the page as well as between
+  // each region, so 1 is added.
+  return (page_layout.margin_left +
+          page_layout.content_width +
+          page_layout.margin_right -
+          (printing::kSettingHeaderFooterHorizontalRegions + 1) *
+           printing::kSettingHeaderFooterInterstice) /
+           printing::kSettingHeaderFooterHorizontalRegions;
+}
+
+// Given a text, the positions, and the paint object, this method gets the
+// coordinates and prints the text at those coordinates on the canvas.
+void PrintHeaderFooterText(
+    string16 text,
+    SkPaint paint,
+    skia::VectorCanvas& canvas,
+    printing::HorizontalHeaderFooterPosition horizontal_position,
+    printing::VerticalHeaderFooterPosition vertical_position,
+    float webkit_scale_factor,
+    const PageSizeMargins& page_layout,
+    SkScalar max_text_width,
+    gfx::Font font,
+    SkScalar height_to_baseline) {
+  text = ui::ElideText(text, font, ConvertPointsToPixelDouble(max_text_width),
+                       false);
+
+  SkPoint text_location;
+  size_t text_byte_length = text.length() * sizeof(char16);
+  // Get the (x, y) coordinate from where printing of the current text should
+  // start depending on the horizontal alignment (LEFT, RIGHT, CENTER) and
+  // vertical alignment (TOP, BOTTOM).
+  SkScalar text_width_in_points = paint.measureText(text.c_str(),
+                                                    text_byte_length);
+  SkScalar x = 0;
+  switch (horizontal_position) {
+    case printing::LEFT: {
+      x = -page_layout.margin_left +

[kmadhusu, 2011/07/26 20:27:50]

Can you rewrite this statement as follows:

x = printing::kSettingHeaderFooterInterstice - page_layout.margin_left;

[Aayush Kumar, 2011/07/28 17:28:41]

Done.

+          printing::kSettingHeaderFooterInterstice;
+      break;
+    }
+    case printing::RIGHT: {
+      x = (page_layout.content_width + page_layout.margin_right -

[kmadhusu, 2011/07/26 20:27:50]

nit: This statement does not require paranthesis since it involves arithmetic
addition and subtraction.

[Aayush Kumar, 2011/07/28 17:28:41]

Done.

+           (printing::kSettingHeaderFooterInterstice + text_width_in_points));
+      break;
+    }
+    case printing::CENTER: {
+      SkScalar available_width = GetSegmentWidth(page_layout);
+      x = available_width - page_layout.margin_left +
+          (available_width - text_width_in_points) / 2;
+      break;
+    }
+    default: {
+      NOTREACHED();
+    }
+  }
+
+  SkScalar y = 0;
+  switch (vertical_position) {
+    case printing::TOP: {
+      y = -page_layout.margin_top - height_to_baseline +
+          printing::kSettingHeaderFooterInterstice;

[kmadhusu, 2011/07/26 20:27:50]

How about:

y = printing::kSettingHeaderFooterInterstice - page_layout.margin_top -
height_to_baseline;

[Aayush Kumar, 2011/07/28 17:28:41]

Done.

+      break;
+    }
+    case printing::BOTTOM: {
+      y = page_layout.margin_bottom + page_layout.content_height -
+          printing::kSettingHeaderFooterInterstice - height_to_baseline;
+      break;
+    }
+    default: {
+      NOTREACHED();
+    }
+  }
+
+  text_location.set(x / webkit_scale_factor, y / webkit_scale_factor);
+  paint.setTextSize(paint.getTextSize() / webkit_scale_factor);
+  canvas.drawText(text.c_str(), text_byte_length, text_location.x(),
+                   text_location.y(), paint);

[kmadhusu, 2011/07/26 20:27:50]

style nit: Fix the indentation

[Aayush Kumar, 2011/07/28 17:28:41]

Done.

+}
+#endif  // USE_SKIA
 }  // namespace
 
+#if defined(USE_SKIA)
+void PrintHeaderAndFooter(SkDevice* device,
+                          skia::VectorCanvas& canvas,
+                          int page_number,
+                          int total_pages,
+                          float webkit_scale_factor,
+                          const PageSizeMargins& page_layout,
+                          const DictionaryValue* header_footer_info) {

[kmadhusu, 2011/07/26 20:27:50]

Can you pass header_footer_info as a "const DictionaryValue&"?

[Aayush Kumar, 2011/07/28 17:28:41]

Done.

+  // Set the drawing area to draw in the margins.
+  static_cast<skia::VectorPlatformDeviceSkia*>(device)->setDrawingArea(
+      SkPDFDevice::kMargin_DrawingArea);
+
+  // Setting up styles for the headers and footers text.
+  SkPaint paint;
+  paint.setColor(SK_ColorBLACK);
+  paint.setTextEncoding(SkPaint::kUTF16_TextEncoding);
+  paint.setTextSize(printing::kSettingHeaderFooterFontSize);
+  gfx::Font font(UTF8ToUTF16(printing::kSettingHeaderFooterFontName),
+                 ceil(ConvertPointsToPixelDouble(
+                     printing::kSettingHeaderFooterFontSize)));
+  paint.setTypeface(SkTypeface::CreateFromName(
+      UTF16ToUTF8(font.GetFontName()).c_str(), SkTypeface::kNormal));
+
+  // Ensure we have enough space to print above and below the page to print
+  // headers.
+  string16 date = base::TimeFormatShortDateNumeric(Time::Now());
+  string16 title;
+  if (!header_footer_info->GetString(printing::kSettingHeaderFooterTitle,
+                                     &title)) {
+    NOTREACHED();
+  }
+
+  SkRect header_bounds;
+  string16 header_text = date + title;
+  paint.measureText(header_text.c_str(), header_text.length() * sizeof(char16),
+                    &header_bounds, 0);
+
+  SkScalar text_height =
+      printing::kSettingHeaderFooterInterstice + header_bounds.height();
+
+  if (text_height > page_layout.margin_top)
+    return;
+
+  // Ensure we have enough space to print above and below the page to print
+  // footers.
+  string16 page_of_total_pages = base::IntToString16(page_number) +
+                                 UTF8ToUTF16("/") +
+                                 base::IntToString16(total_pages);
+  std::string url;
+  if (!header_footer_info->GetString(printing::kSettingHeaderFooterURL,
+                                     &url)) {
+    NOTREACHED();
+  }
+
+  SkRect footer_bounds;
+  string16 footer_text = page_of_total_pages + UTF8ToUTF16(url);
+  paint.measureText(footer_text.c_str(), footer_text.length() * sizeof(char16),
+                    &footer_bounds, 0);
+
+  text_height =
+      printing::kSettingHeaderFooterInterstice + footer_bounds.height();
+
+  if (text_height > page_layout.margin_bottom)
+    return;
+
+  SkScalar segment_width = GetSegmentWidth(page_layout);
+  // Print the Date.
+  PrintHeaderFooterText(date, paint, canvas, printing::LEFT, printing::TOP,
+                        webkit_scale_factor, page_layout, segment_width,
+                        font, header_bounds.top());
+
+  // Print the title.
+  SkScalar date_width = paint.measureText(date.c_str(),
+                                          date.length() * sizeof(char16));
+  // Calculate the available title width. If the date string is not long
+  // enough, then, we increase the available space we have for the title.
+  // Assumes there is no header text to RIGHT of title.
+  SkScalar max_title_width = std::min(2 * segment_width,
+                                      2 * (segment_width - date_width) +
+                                          segment_width);
+  PrintHeaderFooterText(title, paint, canvas, printing::CENTER,
+                        printing::TOP, webkit_scale_factor, page_layout,
+                        max_title_width, font, header_bounds.top());
+
+  // Print the page numbers at the bottom right corner of page.
+  PrintHeaderFooterText(page_of_total_pages, paint, canvas, printing::RIGHT,
+                        printing::BOTTOM, webkit_scale_factor,
+                        page_layout, segment_width, font,
+                        footer_bounds.bottom());
+
+  // Print the URL.
+  GURL gurl(url);
+  SkScalar page_width = paint.measureText(
+      page_of_total_pages.c_str(),
+      page_of_total_pages.length() * sizeof(char16));
+
+  // Calculate the available URL width. We increase the available URL width
+  // if the |page_of_total_pages| string isn't long enough.
+  // Assumes no footer text being printed in the CENTER.
+  SkScalar max_url_width =
+      (page_layout.content_width + page_layout.margin_left +
+       page_layout.margin_right) * 3 / 4;
+  max_url_width = std::min(max_url_width,
+                           2 * (segment_width - page_width) + segment_width);
+  string16 url_elided = ui::ElideUrl(gurl, font,
+                                     ConvertPointsToPixelDouble(max_url_width),
+                                     std::string());
+  PrintHeaderFooterText(url_elided, paint, canvas, printing::LEFT,
+                        printing::BOTTOM, webkit_scale_factor,
+                        page_layout, max_url_width, font,
+                        footer_bounds.bottom());
+
+  // Restore the drawing area to draw in the content area.
+  static_cast<skia::VectorPlatformDeviceSkia*>(device)->setDrawingArea(
+      SkPDFDevice::kContent_DrawingArea);
+}
+#endif  // USE_SKIA
+
 PrepareFrameAndViewForPrint::PrepareFrameAndViewForPrint(
     const PrintMsg_Print_Params& print_params,
     WebFrame* frame,
@@ -726,6 +943,23 @@ bool PrintWebViewHelper::UpdatePrintSettings(
     return false;
 
   print_pages_params_.reset(new PrintMsg_PrintPages_Params(settings));
+  // Getting Header and Footer settings.
+  bool display_header_footer;
+  if (!job_settings.GetBoolean(printing::kSettingHeaderFooter,
+                               &display_header_footer)) {
+    NOTREACHED();
+  }
+  print_pages_params_->params.display_header_footer = display_header_footer;
+  std::string url;
+  if (!job_settings.GetString(printing::kSettingHeaderFooterURL, &url))

[kmadhusu, 2011/07/26 20:27:50]

Can you merge the if conditions @line 948, 954 and 957 together?

[Aayush Kumar, 2011/07/28 17:28:41]

Done.

+    NOTREACHED();
+  header_footer_info_.reset(new DictionaryValue());
+  header_footer_info_->SetString(printing::kSettingHeaderFooterURL, url);
+  string16 title;
+  if (!job_settings.GetString(printing::kSettingHeaderFooterTitle, &title))
+    NOTREACHED();
+  header_footer_info_->SetString(printing::kSettingHeaderFooterTitle, title);
+
   Send(new PrintHostMsg_DidGetDocumentCookie(routing_id(),
                                              settings.params.document_cookie));
   return true;