Factor out text measurement from wxDC and wxWindow into wxTextMeasure.

Add a new private wxTextMeasure class implementing methods for measuring text
and move the often duplicated (but not always identically) code for doing the
same from wxDC and wxWindow into it.

Currently this class is only really implemented in wxMSW and wxGTK.

Also extend the test for text measuring functions and rename it to
MeasuringTextTestCase from MeasuringContextTestCase as it's not wxGC-specific
any more.

Closes #14705.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72699 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Vadim Zeitlin
2012-10-17 22:35:49 +00:00
parent 28dc9371d1
commit 8cd79b7af0
24 changed files with 1616 additions and 396 deletions

185
src/gtk/textmeasure.cpp Normal file
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///////////////////////////////////////////////////////////////////////////////
// Name: src/gtk/textmeasure.cpp
// Purpose: wxTextMeasure implementation for wxGTK
// Author: Manuel Martin
// Created: 2012-10-05
// Copyright: (c) 1997-2012 wxWidgets team
// Licence: wxWindows licence
///////////////////////////////////////////////////////////////////////////////
// ============================================================================
// declarations
// ============================================================================
// ----------------------------------------------------------------------------
// headers
// ----------------------------------------------------------------------------
// for compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"
#ifndef WX_PRECOMP
#include "wx/window.h"
#endif //WX_PRECOMP
#include "wx/private/textmeasure.h"
#include "wx/fontutil.h"
#include "wx/gtk/private.h"
#ifndef __WXGTK3__
#include "wx/gtk/dcclient.h"
#endif
// ============================================================================
// wxTextMeasure implementation
// ============================================================================
void wxTextMeasure::Init()
{
wxASSERT_MSG( m_font, wxT("wxTextMeasure needs a valid wxFont") );
#ifndef __WXGTK3__
m_wdc = NULL;
#endif // GTK+ < 3
m_context = NULL;
m_layout = NULL;
}
// Get Gtk needed elements, if we have not them yet.
void wxTextMeasure::BeginMeasuring()
{
if ( m_dc )
{
#ifndef __WXGTK3__
m_wdc = wxDynamicCast(m_dc->GetImpl(), wxWindowDCImpl);
if ( m_wdc )
{
m_context = m_wdc->m_context;
m_layout = m_wdc->m_layout;
}
#endif // GTK+ < 3
}
else if ( m_win )
{
m_context = gtk_widget_get_pango_context( m_win->GetHandle() );
if ( m_context )
m_layout = pango_layout_new(m_context);
}
// set the font to use
if ( m_layout )
{
pango_layout_set_font_description(m_layout,
m_font->GetNativeFontInfo()->description);
}
}
void wxTextMeasure::EndMeasuring()
{
if ( !m_layout )
return;
#ifndef __WXGTK3__
if ( m_wdc )
{
// Reset dc own font description
pango_layout_set_font_description( m_wdc->m_layout, m_wdc->m_fontdesc );
}
else
#endif // GTK+ < 3
{
g_object_unref (m_layout);
}
}
// Notice we don't check here the font. It is supposed to be OK before the call.
void wxTextMeasure::DoGetTextExtent(const wxString& string,
wxCoord *width,
wxCoord *height,
wxCoord *descent,
wxCoord *externalLeading)
{
if ( !m_context )
{
*width =
*height = 0;
return;
}
// Set layout's text
const wxCharBuffer dataUTF8 = wxGTK_CONV_FONT(string, *m_font);
if ( !dataUTF8 )
{
// hardly ideal, but what else can we do if conversion failed?
wxLogLastError(wxT("GetTextExtent"));
return;
}
pango_layout_set_text(m_layout, dataUTF8, -1);
if ( m_dc )
{
// in device units
pango_layout_get_pixel_size(m_layout, width, height);
}
else // win
{
// the logical rect bounds the ink rect
PangoRectangle rect;
pango_layout_get_extents(m_layout, NULL, &rect);
*width = PANGO_PIXELS(rect.width);
*height = PANGO_PIXELS(rect.height);
}
if (descent)
{
PangoLayoutIter *iter = pango_layout_get_iter(m_layout);
int baseline = pango_layout_iter_get_baseline(iter);
pango_layout_iter_free(iter);
*descent = *height - PANGO_PIXELS(baseline);
}
if (externalLeading)
{
// No support for MSW-like "external leading" in Pango.
*externalLeading = 0;
}
}
bool wxTextMeasure::DoGetPartialTextExtents(const wxString& text,
wxArrayInt& widths,
double WXUNUSED(scaleX))
{
// Set layout's text
const wxCharBuffer dataUTF8 = wxGTK_CONV_FONT(text, *m_font);
if ( !dataUTF8 )
{
// hardly ideal, but what else can we do if conversion failed?
wxLogLastError(wxT("GetPartialTextExtents"));
return false;
}
pango_layout_set_text(m_layout, dataUTF8, -1);
// Calculate the position of each character based on the widths of
// the previous characters
// Code borrowed from Scintilla's PlatGTK
PangoLayoutIter *iter = pango_layout_get_iter(m_layout);
PangoRectangle pos;
pango_layout_iter_get_cluster_extents(iter, NULL, &pos);
size_t i = 0;
while (pango_layout_iter_next_cluster(iter))
{
pango_layout_iter_get_cluster_extents(iter, NULL, &pos);
int position = PANGO_PIXELS(pos.x);
widths[i++] = position;
}
const size_t len = text.length();
while (i < len)
widths[i++] = PANGO_PIXELS(pos.x + pos.width);
pango_layout_iter_free(iter);
return true;
}