CefPrintHandler

Header: cef_print_handler.h
Interfaces: CefPrintDialogCallback, CefPrintJobCallback, CefPrintHandler
Category: Browser Handlers

Overview

User-implemented handler interfaces returned from CefClient and registered with CefBrowserHost.

CefPrintDialogCallback

Source File: include/cef_print_handler.h

Process / Thread Context: Browser process / UI thread. USER-CALLED (source=library).

Purpose: Async continuation for print-dialog requests.

Methods

void Continue(CefRefPtr<CefPrintSettings> settings)

Parameters:

• settings: Print settings to use.

Return Value: None.

Usage Instruction: Continue printing with the specified settings.

Threading Constraint: Threading constraint not specified per-method; class comment for CefPrintHandler says UI thread.

void Cancel()

Parameters:

• None.

Return Value: None.

Usage Instruction: Cancel printing.

Threading Constraint: Threading constraint not specified per-method.

CefPrintJobCallback

Source File: include/cef_print_handler.h

Process / Thread Context: Browser process / UI thread. USER-CALLED (source=library).

Purpose: Async continuation for print-job completion.

Methods

void Continue()

Parameters:

• None.

Return Value: None.

Usage Instruction: Indicate completion of the print job.

Threading Constraint: Threading constraint not specified per-method.

CefPrintHandler

Source File: include/cef_print_handler.h

Process / Thread Context: Browser process / UI thread. USER-IMPLEMENTED (source=client); returned from CefClient::GetPrintHandler(). Header explicitly notes: "Implement this interface to handle printing on Linux." and "If a print handler is not provided then printing will not be supported on the Linux platform."

Purpose: Handle Linux printing: receive print start/stop notifications, populate print settings, show print dialog, send print job, and provide PDF paper size.

Methods

CefSize GetPdfPaperSize(CefRefPtr<CefBrowser> browser, int device_units_per_inch)

Parameters:

• browser: The browser.
• device_units_per_inch: DPI for the device.

Return Value: CefSize paper size in device units; default is empty CefSize().

Usage Instruction: Used with CefBrowserHost::PrintToPDF().

Threading Constraint: UI thread per class comment.

Usage Example

class MyPrintHandler : public CefPrintHandler {
 public:
  void OnPrintStart(CefRefPtr<CefBrowser>) override {}
  void OnPrintSettings(CefRefPtr<CefBrowser>, CefRefPtr<CefPrintSettings> s,
                       bool defaults) override {
    if (defaults) s->SetOrientation(true);
  }
  bool OnPrintDialog(CefRefPtr<CefBrowser>, bool has_sel,
                     CefRefPtr<CefPrintDialogCallback> cb) override {
    // Show GtkPrintDialog; on OK: cb->Continue(settings); else cb->Cancel();
    return true;
  }
  bool OnPrintJob(CefRefPtr<CefBrowser>, const CefString& name,
                  const CefString& pdf_path,
                  CefRefPtr<CefPrintJobCallback> cb) override {
    // Send pdf_path to printer; then:
    cb->Continue();
    return true;
  }
  void OnPrintReset(CefRefPtr<CefBrowser>) override {}
  CefSize GetPdfPaperSize(CefRefPtr<CefBrowser>, int dpi) override {
    return CefSize(8.5 * dpi, 11 * dpi);  // US Letter
  }
  IMPLEMENT_REFCOUNTING(MyPrintHandler);
};

// MyClient::GetPrintHandler() returns this.