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// Copyright (c) 2009 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome/renderer/print_web_view_helper.h"
#include "base/file_descriptor_posix.h"
#include "base/logging.h"
#include "chrome/common/render_messages.h"
#include "printing/native_metafile.h"
#include "skia/ext/vector_canvas.h"
#include "webkit/api/public/WebFrame.h"
using WebKit::WebFrame;
void PrintWebViewHelper::Print(WebFrame* frame, bool script_initiated) {
// If still not finished with earlier print request simply ignore.
if (IsPrinting())
return;
// TODO(myhuang): Get printing parameters via IPC.
// For testing purpose, we hard-coded printing parameters here.
// The paper size is US Letter (8.5 in. by 11 in.).
// Using default margins:
// Left = 0.25 in.
// Right = 0.25 in.
// Top = 0.25 in.
// Bottom = 0.56 in.
const int kDPI = 72;
const int kWidth = static_cast<int>((8.5-0.25-0.25) * kDPI);
const int kHeight = static_cast<int>((11-0.25-0.56) * kDPI);
ViewMsg_Print_Params default_settings;
default_settings.printable_size = gfx::Size(kWidth, kHeight);
default_settings.dpi = kDPI;
default_settings.min_shrink = 1.25;
default_settings.max_shrink = 2.0;
default_settings.desired_dpi = kDPI;
default_settings.document_cookie = 0;
default_settings.selection_only = false;
ViewMsg_PrintPages_Params print_settings;
print_settings.params = default_settings;
PrintPages(print_settings, frame);
}
void PrintWebViewHelper::PrintPages(const ViewMsg_PrintPages_Params& params,
WebFrame* frame) {
PrepareFrameAndViewForPrint prep_frame_view(params.params,
frame,
frame->view());
int page_count = prep_frame_view.GetExpectedPageCount();
// TODO(myhuang): Send ViewHostMsg_DidGetPrintedPagesCount.
if (page_count == 0)
return;
// We only can use PDF in the renderer because Cairo needs to create a
// temporary file for a PostScript surface.
printing::NativeMetafile metafile(printing::NativeMetafile::PDF);
metafile.Init();
ViewMsg_PrintPage_Params print_page_params;
print_page_params.params = params.params;
const gfx::Size& canvas_size = prep_frame_view.GetPrintCanvasSize();
if (params.pages.empty()) {
for (int i = 0; i < page_count; ++i) {
print_page_params.page_number = i;
PrintPage(print_page_params, canvas_size, frame, &metafile);
}
} else {
for (size_t i = 0; i < params.pages.size(); ++i) {
print_page_params.page_number = params.pages[i];
PrintPage(print_page_params, canvas_size, frame, &metafile);
}
}
metafile.Close();
// Get the size of the resulting metafile.
unsigned int buf_size = metafile.GetDataSize();
DCHECK_GT(buf_size, 0u);
base::FileDescriptor fd;
int fd_in_browser = -1;
// Ask the browser to open a file for us.
if (!Send(new ViewHostMsg_AllocateTempFileForPrinting(&fd,
&fd_in_browser))) {
return;
}
if (!metafile.SaveTo(fd))
return;
// Tell the browser we've finished writing the file.
Send(new ViewHostMsg_TempFileForPrintingWritten(fd_in_browser));
}
void PrintWebViewHelper::PrintPage(const ViewMsg_PrintPage_Params& params,
const gfx::Size& canvas_size,
WebFrame* frame,
printing::NativeMetafile* metafile) {
// Since WebKit extends the page width depending on the magical shrink
// factor we make sure the canvas covers the worst case scenario
// (x2.0 currently). PrintContext will then set the correct clipping region.
int size_x = static_cast<int>(canvas_size.width() * params.params.max_shrink);
int size_y = static_cast<int>(canvas_size.height() *
params.params.max_shrink);
// Calculate the dpi adjustment.
float shrink = static_cast<float>(canvas_size.width()) /
params.params.printable_size.width();
cairo_t* cairo_context = metafile->StartPage(size_x, size_y);
if (!cairo_context) {
// TODO(myhuang): We should handle such kind of error further!
// We already have had DLOG(ERROR) in NativeMetafile::StartPage(),
// log the error here, too?
return;
}
skia::VectorCanvas canvas(cairo_context, size_x, size_y);
float webkit_shrink = frame->printPage(params.page_number, &canvas);
if (webkit_shrink <= 0) {
NOTREACHED() << "Printing page " << params.page_number << " failed.";
} else {
// Update the dpi adjustment with the "page shrink" calculated in webkit.
shrink /= webkit_shrink;
}
// TODO(myhuang): We should handle transformation for paper margins.
// TODO(myhuang): We should render the header and the footer.
// Done printing. Close the device context to retrieve the compiled metafile.
if (!metafile->FinishPage(shrink)) {
NOTREACHED() << "metafile failed";
}
}
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