Factor out text measurement from wxDC and wxWindow into wxTextMeasure.

[wxWidgets.git] / src / msw / textmeasure.cpp

diff --git a/src/msw/textmeasure.cpp b/src/msw/textmeasure.cpp
new file mode 100644 (file)
index 0000000..c2b364a
--- /dev/null
+++ b/src/msw/textmeasure.cpp
@@ -0,0 +1,172 @@
+///////////////////////////////////////////////////////////////////////////////
+// Name:        src/msw/textmeasure.cpp
+// Purpose:     wxTextMeasure implementation for wxMSW
+// Author:      Manuel Martin
+// Created:     2012-19-05
+// RCS-ID:
+// Copyright:
+// Licence:     wxWindows licence
+///////////////////////////////////////////////////////////////////////////////
+
+// ============================================================================
+// declarations
+// ============================================================================
+
+// ----------------------------------------------------------------------------
+// headers
+// ----------------------------------------------------------------------------
+
+// for compilers that support precompilation, includes "wx.h".
+#include "wx/wxprec.h"
+
+#ifdef __BORLANDC__
+    #pragma hdrstop
+#endif
+
+#include "wx/msw/private.h"
+#include "wx/msw/dc.h"
+
+#ifndef WX_PRECOMP
+    #include "wx/window.h"
+    #include "wx/font.h"
+#endif //WX_PRECOMP
+
+#include "wx/private/textmeasure.h"
+
+// ============================================================================
+// wxTextMeasure implementation
+// ============================================================================
+
+void wxTextMeasure::Init()
+{
+    m_hdc = NULL;
+    m_hfontOld = NULL;
+}
+
+void wxTextMeasure::BeginMeasuring()
+{
+    if ( m_dc )
+    {
+        m_hdc = m_dc->GetHDC();
+
+        // Non-native wxDC subclasses should override their DoGetTextExtent()
+        // and other methods.
+        wxASSERT_MSG( m_hdc, wxS("Must not be used with non-native wxDCs") );
+    }
+    else if ( m_win )
+    {
+        m_hdc = ::GetDC(GetHwndOf(m_win));
+    }
+
+    if ( m_font )
+        m_hfontOld = (HFONT)::SelectObject(m_hdc, GetHfontOf(*m_font));
+}
+
+void wxTextMeasure::EndMeasuring()
+{
+    if ( m_hfontOld )
+    {
+        ::SelectObject(m_hdc, m_hfontOld);
+        m_hfontOld = NULL;
+    }
+
+    if ( m_win )
+        ::ReleaseDC(GetHwndOf(m_win), m_hdc);
+    //else: our HDC belongs to m_dc, don't touch it
+
+    m_hdc = NULL;
+}
+
+// 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)
+{
+    SIZE sizeRect;
+    const size_t len = string.length();
+    if ( !::GetTextExtentPoint32(m_hdc, string.t_str(), len, &sizeRect) )
+    {
+        wxLogLastError(wxT("GetTextExtentPoint32()"));
+    }
+
+#if !defined(_WIN32_WCE) || (_WIN32_WCE >= 400)
+    // the result computed by GetTextExtentPoint32() may be too small as it
+    // accounts for under/overhang of the first/last character while we want
+    // just the bounding rect for this string so adjust the width as needed
+    // (using API not available in 2002 SDKs of WinCE)
+    if ( len > 0 )
+    {
+        ABC widthABC;
+        const wxChar chFirst = *string.begin();
+        if ( ::GetCharABCWidths(m_hdc, chFirst, chFirst, &widthABC) )
+        {
+            if ( widthABC.abcA < 0 )
+                sizeRect.cx -= widthABC.abcA;
+
+            if ( len > 1 )
+            {
+                const wxChar chLast = *string.rbegin();
+                ::GetCharABCWidths(m_hdc, chLast, chLast, &widthABC);
+            }
+            //else: we already have the width of the last character
+
+            if ( widthABC.abcC < 0 )
+                sizeRect.cx -= widthABC.abcC;
+        }
+        //else: GetCharABCWidths() failed, not a TrueType font?
+    }
+#endif // !defined(_WIN32_WCE) || (_WIN32_WCE >= 400)
+
+    *width = sizeRect.cx;
+    *height = sizeRect.cy;
+
+    if ( descent || externalLeading )
+    {
+        TEXTMETRIC tm;
+        ::GetTextMetrics(m_hdc, &tm);
+        if ( descent )
+            *descent = tm.tmDescent;
+        if ( externalLeading )
+            *externalLeading = tm.tmExternalLeading;
+    }
+}
+
+bool wxTextMeasure::DoGetPartialTextExtents(const wxString& text,
+                                            wxArrayInt& widths,
+                                            double WXUNUSED(scaleX))
+{
+    static int maxLenText = -1;
+    static int maxWidth = -1;
+
+    if (maxLenText == -1)
+    {
+        // Win9x and WinNT+ have different limits
+        int version = wxGetOsVersion();
+        maxLenText = version == wxOS_WINDOWS_NT ? 65535 : 8192;
+        maxWidth =   version == wxOS_WINDOWS_NT ? INT_MAX : 32767;
+    }
+
+    int len = text.length();
+    if ( len > maxLenText )
+        len = maxLenText;
+
+    int fit = 0;
+    SIZE sz = {0,0};
+    if ( !::GetTextExtentExPoint(m_hdc,
+                                 text.t_str(), // string to check
+                                 len,
+                                 maxWidth,
+                                 &fit,         // [out] count of chars
+                                               // that will fit
+                                 &widths[0],   // array to fill
+                                 &sz) )
+    {
+        wxLogLastError(wxT("GetTextExtentExPoint"));
+
+        return false;
+    }
+
+    return true;
+}