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 7ad456ff47cbbfc7acd57c6b0aca0fa3404d0e73..9e198b2680a6fc4035086170016b423fbe80b611 100644
--- a/chrome/renderer/print_web_view_helper.cc
+++ b/chrome/renderer/print_web_view_helper.cc
@@ -36,8 +36,22 @@
 #include "content/common/view_messages.h"
 #endif
 
+#if defined(USE_SKIA)
+#include <algorithm>
+#include <cmath>
+#include "base/i18n/time_formatting.h"
+#include "base/string_number_conversions.h"
+#include "base/time.h"
+#include "skia/ext/vector_canvas.h"
+#include "skia/ext/vector_platform_device_skia.h"
+#include "third_party/skia/include/core/SkTypeface.h"
+#include "ui/base/text/text_elider.h"
+#endif

[vandebo (ex-Chrome), 2011/08/01 21:07:37]

  // USE_SKIA

[Aayush Kumar, 2011/08/02 00:18:13]

Done.

+
+using base::Time;
 using printing::ConvertPixelsToPoint;
 using printing::ConvertPixelsToPointDouble;
+using printing::ConvertPointsToPixelDouble;
 using printing::ConvertUnit;
 using printing::ConvertUnitDouble;
 using WebKit::WebConsoleMessage;
@@ -87,6 +101,8 @@ 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());
 }
@@ -101,8 +117,209 @@ void CalculatePrintCanvasSize(const PrintMsg_Print_Params& print_params,
                                  print_params.desired_dpi));
 }
 
+#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 +

[vandebo (ex-Chrome), 2011/08/01 21:07:37]

I'm actually not sure of the indent here... should this go in four to account
for the ( ?

[Aayush Kumar, 2011/08/02 00:18:13]

Done.

+          page_layout.margin_right -
+          (printing::kSettingHeaderFooterHorizontalRegions + 1) *
+           printing::kSettingHeaderFooterInterstice) /

[vandebo (ex-Chrome), 2011/08/01 21:07:37]

nit: extra space.  Sorry if I mislead you here before.  The the ()'s matched on
the previous line.

[Aayush Kumar, 2011/08/02 00:18:13]

Done.

+           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,

[vandebo (ex-Chrome), 2011/08/01 21:07:37]

const SkPaint& paint

[Aayush Kumar, 2011/08/02 00:18:13]

I don't want to pass a reference here, since, I am changing the text size within
paint which I don't want reflected in the parent function.
On 2011/08/01 21:07:37, vandebo wrote:

+    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,

[vandebo (ex-Chrome), 2011/08/01 21:07:37]

const gfx::Font& font

[Aayush Kumar, 2011/08/02 00:18:13]

Done.

+    SkScalar height_to_baseline) {

[vandebo (ex-Chrome), 2011/08/01 21:07:37]

nit: this might be better named space_for_descenders ?

[Aayush Kumar, 2011/08/02 00:18:13]

Done.

+  text = ui::ElideText(text, font, ConvertPointsToPixelDouble(max_text_width),
+                       false);
+
+  SkPoint text_location;

[vandebo (ex-Chrome), 2011/08/01 21:07:37]

I don't think you need both this and x & y; use one or the other.

[Aayush Kumar, 2011/08/02 00:18:13]

Done.

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

[vandebo (ex-Chrome), 2011/08/01 21:07:37]

This is putting the text just above the content area.  Do we want to put this
just below the top of the page?

[Aayush Kumar, 2011/08/02 00:18:13]

No, this actually doesn't do that.  It places it right below the top of the
page.  (Notice the "-page_layout.margin_top"
On 2011/08/01 21:07:37, vandebo wrote:

+          page_layout.margin_top - height_to_baseline;
+      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);
+}
+#endif  // USE_SKIA
+
 }  // namespace
 
+#if defined(USE_SKIA)
+// static - Not anonymous so that platform implementations can use it.
+void PrintWebViewHelper::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) {
+  // Set the drawing area to draw in the margins.

[vandebo (ex-Chrome), 2011/08/01 21:07:37]

nit: comment isn't needed.

[Aayush Kumar, 2011/08/02 00:18:13]

Done.

[vandebo (ex-Chrome), 2011/08/03 19:00:05]

Done in spirit only ;-)

[Aayush Kumar, 2011/08/04 18:25:04]

Done this time - sorry :)

+  static_cast<skia::VectorPlatformDeviceSkia*>(device)->setDrawingArea(
+      SkPDFDevice::kMargin_DrawingArea);
+
+  // Setting up styles for the headers and footers text.

[vandebo (ex-Chrome), 2011/08/01 21:07:37]

nit: comment isn't needed

[Aayush Kumar, 2011/08/02 00:18:13]

Can I leave this comment?  I found it a lot easier to read my own code with
these comments :)
On 2011/08/01 21:07:37, vandebo wrote:

[vandebo (ex-Chrome), 2011/08/03 19:00:05]

Meta comment - it's harder to see replies when you top post, please bottom post,
at least for short comments.

[Aayush Kumar, 2011/08/04 18:25:04]

Ahh okay :)  It's weird though because when I click the reply button, the cursor
is on top of the box, whereas when I click on "Done" - it automatically adds
that to the end.

+  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.

[vandebo (ex-Chrome), 2011/08/01 21:07:37]

I think this comment and the one on 250 should go down to 269?  But then it
might not be needed?

[Aayush Kumar, 2011/08/02 00:18:13]

This is actually checked for on line 244.  
On 2011/08/01 21:07:37, vandebo wrote:

[vandebo (ex-Chrome), 2011/08/03 19:00:05]

Why don't we do this... move the conditionals about fitting or not down to the
calls to PrintHeaderFooterText (to satisfy my next comment) then the code
between here and there will be calculating the height the text, and you can have
a comment, "Get the height of the headers and footers to ensure it will fit in
the margins" or something along those lines.

[Aayush Kumar, 2011/08/04 18:25:04]

Done.

+  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;

[vandebo (ex-Chrome), 2011/08/01 21:07:37]

What if there is room for the footers, but not the headers?

[Aayush Kumar, 2011/08/02 00:18:13]

I am going for all or nothing.  Just want to be consistent. :)
On 2011/08/01 21:07:37, vandebo wrote:

[vandebo (ex-Chrome), 2011/08/03 19:00:05]

It seems to me that if there's still room for the footers and the user said they
want footers, we should print footers.

[Aayush Kumar, 2011/08/04 18:25:04]

Done.

+
+  // 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,
@@ -776,6 +993,21 @@ bool PrintWebViewHelper::UpdatePrintSettings(
     return false;
 
   print_pages_params_.reset(new PrintMsg_PrintPages_Params(settings));
+  // Getting Header and Footer settings.
+  bool display_header_footer;
+  string16 title;
+  std::string url;
+  if (!job_settings.GetBoolean(printing::kSettingHeaderFooter,

[kmadhusu, 2011/08/01 17:17:08]

(repeating our in-person conversation): Remove the header & footer settings info
from job_settings after reading those values.

[Aayush Kumar, 2011/08/02 00:18:13]

Done.

+                               &display_header_footer) ||
+      !job_settings.GetString(printing::kSettingHeaderFooterTitle, &title) ||
+      !job_settings.GetString(printing::kSettingHeaderFooterURL, &url)) {
+    NOTREACHED();
+  }
+  print_pages_params_->params.display_header_footer = display_header_footer;
+  header_footer_info_.reset(new DictionaryValue());
+  header_footer_info_->SetString(printing::kSettingHeaderFooterURL, url);

[kmadhusu, 2011/08/01 17:17:08]

Populate the header_footer_info_ only if |display_header_footer| is true.

[Aayush Kumar, 2011/08/02 00:18:13]

Done.

+  header_footer_info_->SetString(printing::kSettingHeaderFooterTitle, title);
+
   Send(new PrintHostMsg_DidGetDocumentCookie(routing_id(),
                                              settings.params.document_cookie));
   return true;