// Created: 03.03.03 (replaces the old file with the same name)
// RCS-ID: $Id$
// Copyright: (c) 2003 Vadim Zeitlin <vadim@wxwindows.org>
-// License: wxWindows licence
+// Licence: wxWindows licence
///////////////////////////////////////////////////////////////////////////////
/*
TODO: support for palettes is very incomplete, several functions simply
ignore them (we should select and realize the palette, if any, before
- caling GetDIBits() in the DC we use with it and we shouldn't use
- GetBitmapBits() at all because we can't do it with it)
+ caling GetDIBits() in the DC we use with it.
*/
// ============================================================================
#pragma hdrstop
#endif
+#if wxUSE_WXDIB
+
#ifndef WX_PRECOMP
#include "wx/string.h"
#include "wx/log.h"
+ #include "wx/intl.h"
+ #include "wx/bitmap.h"
+ #include "wx/image.h"
#endif //WX_PRECOMP
-#include "wx/bitmap.h"
-#include "wx/intl.h"
#include "wx/file.h"
#include <stdio.h>
#include <stdlib.h>
-#if !defined(__MWERKS__) && !defined(__SALFORDC__)
#include <memory.h>
-#endif
-
-#ifdef __GNUWIN32_OLD__
- #include "wx/msw/gnuwin32/extra.h"
-#endif
-#include "wx/image.h"
#include "wx/msw/dib.h"
+#ifdef __WXWINCE__
+ #include <shellapi.h> // for SHLoadDIBitmap()
+#endif
+
// ----------------------------------------------------------------------------
// private functions
// ----------------------------------------------------------------------------
// calculate the number of palette entries needed for the bitmap with this
// number of bits per pixel
-static WORD wxGetNumOfBitmapColors(WORD bitsPerPixel)
+static inline WORD GetNumberOfColours(WORD bitsPerPixel)
{
// only 1, 4 and 8bpp bitmaps use palettes (well, they could be used with
// 24bpp ones too but we don't support this as I think it's quite uncommon)
- return bitsPerPixel <= 8 ? 1 << bitsPerPixel : 0;
+ return (WORD)(bitsPerPixel <= 8 ? 1 << bitsPerPixel : 0);
+}
+
+// wrapper around ::GetObject() for DIB sections
+static inline bool GetDIBSection(HBITMAP hbmp, DIBSECTION *ds)
+{
+ // note that at least under Win9x (this doesn't seem to happen under Win2K
+ // but this doesn't mean anything, of course), GetObject() may return
+ // sizeof(DIBSECTION) for a bitmap which is *not* a DIB section and the way
+ // to check for it is by looking at the bits pointer
+ return ::GetObject(hbmp, sizeof(DIBSECTION), ds) == sizeof(DIBSECTION) &&
+ ds->dsBm.bmBits;
}
// ============================================================================
bool wxDIB::Create(int width, int height, int depth)
{
- // we don't handle the palette yet
- wxASSERT_MSG( depth == 24 || depth == 32,
- _T("unsupported image depth in wxDIB::Create()") );
-
- static const int infosize = sizeof(BITMAPINFOHEADER);
-
- BITMAPINFO *info = (BITMAPINFO *)malloc(infosize);
- wxCHECK_MSG( info, NULL, _T("malloc(BITMAPINFO) failed") );
+ // we don't support formats using palettes right now so we only create
+ // either 24bpp (RGB) or 32bpp (RGBA) bitmaps
+ wxASSERT_MSG( depth, wxT("invalid image depth in wxDIB::Create()") );
+ if ( depth < 24 )
+ depth = 24;
- memset(info, 0, infosize);
+ // allocate memory for bitmap structures
+ BITMAPINFO info;
+ wxZeroMemory(info);
- info->bmiHeader.biSize = infosize;
- info->bmiHeader.biWidth = width;
+ info.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
+ info.bmiHeader.biWidth = width;
// we use positive height here which corresponds to a DIB with normal, i.e.
// bottom to top, order -- normally using negative height (which means
// reversed for MS and hence natural for all the normal people top to
// bottom line scan order) could be used to avoid the need for the image
// reversal in Create(image) but this doesn't work under NT, only Win9x!
- info->bmiHeader.biHeight = height;
+ info.bmiHeader.biHeight = height;
- info->bmiHeader.biPlanes = 1;
- info->bmiHeader.biBitCount = depth;
- info->bmiHeader.biSizeImage = GetLineSize(width, depth)*height;
+ info.bmiHeader.biPlanes = 1;
+ info.bmiHeader.biBitCount = (WORD)depth;
+ info.bmiHeader.biSizeImage = GetLineSize(width, depth)*height;
m_handle = ::CreateDIBSection
(
0, // hdc (unused with DIB_RGB_COLORS)
- info, // bitmap description
+ &info, // bitmap description
DIB_RGB_COLORS, // use RGB, not palette
&m_data, // [out] DIB bits
NULL, // don't use file mapping
0 // file mapping offset (not used here)
);
- free(info);
-
if ( !m_handle )
{
wxLogLastError(wxT("CreateDIBSection"));
return true;
}
-bool wxDIB::Create(const wxBitmap& bmp)
+bool wxDIB::Create(HBITMAP hbmp)
{
- wxCHECK_MSG( bmp.Ok(), false, _T("wxDIB::Create(): invalid bitmap") );
+ wxCHECK_MSG( hbmp, false, wxT("wxDIB::Create(): invalid bitmap") );
+
+ // this bitmap could already be a DIB section in which case we don't need
+ // to convert it to DIB
+ DIBSECTION ds;
+ if ( GetDIBSection(hbmp, &ds) )
+ {
+ m_handle = hbmp;
+
+ // wxBitmap will free it, not we
+ m_ownsHandle = false;
+
+ // copy all the bitmap parameters too as we have them now anyhow
+ m_width = ds.dsBm.bmWidth;
+ m_height = ds.dsBm.bmHeight;
+ m_depth = ds.dsBm.bmBitsPixel;
+
+ m_data = ds.dsBm.bmBits;
+ }
+ else // no, it's a DDB -- convert it to DIB
+ {
+ // prepare all the info we need
+ BITMAP bm;
+ if ( !::GetObject(hbmp, sizeof(bm), &bm) )
+ {
+ wxLogLastError(wxT("GetObject(bitmap)"));
- const int w = bmp.GetWidth();
- const int h = bmp.GetHeight();
- int d = bmp.GetDepth();
- if ( d == -1 )
- d = wxDisplayDepth();
+ return false;
+ }
+
+ int d = bm.bmBitsPixel;
+ if ( d <= 0 )
+ d = wxDisplayDepth();
+
+ if ( !Create(bm.bmWidth, bm.bmHeight, d) || !CopyFromDDB(hbmp) )
+ return false;
+ }
+
+ return true;
+}
- if ( !Create(w, h, d) )
+// Windows CE doesn't have GetDIBits() so use an alternative implementation
+// for it
+//
+// in fact I'm not sure if GetDIBits() is really much better than using
+// BitBlt() like this -- it should be faster but I didn't do any tests, if
+// anybody has time to do them and by chance finds that GetDIBits() is not
+// much faster than BitBlt(), we could always use the Win CE version here
+#ifdef __WXWINCE__
+
+bool wxDIB::CopyFromDDB(HBITMAP hbmp)
+{
+ MemoryHDC hdcSrc;
+ if ( !hdcSrc )
+ return false;
+
+ SelectInHDC selectSrc(hdcSrc, hbmp);
+ if ( !selectSrc )
+ return false;
+
+ MemoryHDC hdcDst;
+ if ( !hdcDst )
+ return false;
+
+ SelectInHDC selectDst(hdcDst, m_handle);
+ if ( !selectDst )
return false;
- // we could have used GetDIBits() too but GetBitmapBits() is simpler
- if ( !::GetBitmapBits
+
+ if ( !::BitBlt(
+ hdcDst,
+ 0, 0, m_width, m_height,
+ hdcSrc,
+ 0, 0,
+ SRCCOPY
+ ) )
+ {
+ wxLogLastError(wxT("BitBlt(DDB -> DIB)"));
+
+ return false;
+ }
+
+ return true;
+}
+
+#else // !__WXWINCE__
+
+bool wxDIB::CopyFromDDB(HBITMAP hbmp)
+{
+ DIBSECTION ds;
+ if ( !GetDIBSection(m_handle, &ds) )
+ {
+ // we're sure that our handle is a DIB section, so this should work
+ wxFAIL_MSG( wxT("GetObject(DIBSECTION) unexpectedly failed") );
+
+ return false;
+ }
+
+ if ( !::GetDIBits
(
- GetHbitmapOf(bmp), // the source DDB
- GetLineSize(w, d)*h, // the number of bytes to copy
- m_data // the pixels will be copied here
+ ScreenHDC(), // the DC to use
+ hbmp, // the source DDB
+ 0, // first scan line
+ m_height, // number of lines to copy
+ ds.dsBm.bmBits, // pointer to the buffer
+ (BITMAPINFO *)&ds.dsBmih, // bitmap header
+ DIB_RGB_COLORS // and not DIB_PAL_COLORS
) )
{
wxLogLastError(wxT("GetDIBits()"));
- return 0;
+ return false;
}
return true;
}
+#endif // __WXWINCE__/!__WXWINCE__
+
// ----------------------------------------------------------------------------
// Loading/saving the DIBs
// ----------------------------------------------------------------------------
bool wxDIB::Load(const wxString& filename)
{
+#ifdef __WXWINCE__
+ m_handle = SHLoadDIBitmap(filename);
+#else // !__WXWINCE__
m_handle = (HBITMAP)::LoadImage
(
wxGetInstance(),
- filename,
+ filename.t_str(),
IMAGE_BITMAP,
0, 0, // don't specify the size
LR_CREATEDIBSECTION | LR_LOADFROMFILE
);
+#endif // __WXWINCE__
+
if ( !m_handle )
{
- wxLogLastError(_T("LoadImage(LR_CREATEDIBSECTION | LR_LOADFROMFILE)"));
+ wxLogLastError(wxT("Loading DIB from file"));
return false;
}
bool wxDIB::Save(const wxString& filename)
{
- wxCHECK_MSG( m_handle, false, _T("wxDIB::Save(): invalid object") );
+ wxCHECK_MSG( m_handle, false, wxT("wxDIB::Save(): invalid object") );
+#if wxUSE_FILE
wxFile file(filename, wxFile::write);
bool ok = file.IsOpened();
if ( ok )
{
DIBSECTION ds;
- if ( !::GetObject(m_handle, sizeof(ds), &ds) )
+ if ( !GetDIBSection(m_handle, &ds) )
{
- wxLogLastError(_T("GetObject(hDIB)"));
+ wxLogLastError(wxT("GetObject(hDIB)"));
}
else
{
file.Write(ds.dsBm.bmBits, sizeImage) == sizeImage;
}
}
+#else // !wxUSE_FILE
+ bool ok = false;
+#endif // wxUSE_FILE/!wxUSE_FILE
if ( !ok )
{
// check for this now rather than trying to find out why it doesn't
// work later
DIBSECTION ds;
- if ( !::GetObject(m_handle, sizeof(ds), &ds) )
+ if ( !GetDIBSection(m_handle, &ds) )
{
- wxLogLastError(_T("GetObject(hDIB)"));
+ wxLogLastError(wxT("GetObject(hDIB)"));
return;
}
// DDB <-> DIB conversions
// ----------------------------------------------------------------------------
+#ifndef __WXWINCE__
+
HBITMAP wxDIB::CreateDDB(HDC hdc) const
{
- wxCHECK_MSG( m_handle, 0, _T("wxDIB::CreateDDB(): invalid object") );
+ wxCHECK_MSG( m_handle, 0, wxT("wxDIB::CreateDDB(): invalid object") );
DIBSECTION ds;
- if ( !::GetObject(m_handle, sizeof(ds), &ds) )
+ if ( !GetDIBSection(m_handle, &ds) )
{
- wxLogLastError(_T("GetObject(hDIB)"));
+ wxLogLastError(wxT("GetObject(hDIB)"));
return 0;
}
- return ConvertToBitmap((BITMAPINFO *)&ds.dsBmih, hdc, ds.dsBm.bmBits);
+ // how many colours are we going to have in the palette?
+ DWORD biClrUsed = ds.dsBmih.biClrUsed;
+ if ( !biClrUsed )
+ {
+ // biClrUsed field might not be set
+ biClrUsed = GetNumberOfColours(ds.dsBmih.biBitCount);
+ }
+
+ if ( !biClrUsed )
+ {
+ return ConvertToBitmap((BITMAPINFO *)&ds.dsBmih, hdc, ds.dsBm.bmBits);
+ }
+ else
+ {
+ // fake a BITMAPINFO w/o bits, just the palette info
+ wxCharBuffer bmi(sizeof(BITMAPINFO) + (biClrUsed - 1)*sizeof(RGBQUAD));
+ BITMAPINFO *pBmi = (BITMAPINFO *)bmi.data();
+ MemoryHDC hDC;
+ // get the colour table
+ SelectInHDC sDC(hDC, m_handle);
+ ::GetDIBColorTable(hDC, 0, biClrUsed, pBmi->bmiColors);
+ memcpy(&pBmi->bmiHeader, &ds.dsBmih, ds.dsBmih.biSize);
+
+ return ConvertToBitmap(pBmi, hdc, ds.dsBm.bmBits);
+ }
}
/* static */
HBITMAP wxDIB::ConvertToBitmap(const BITMAPINFO *pbmi, HDC hdc, void *bits)
{
- wxCHECK_MSG( pbmi, 0, _T("invalid DIB in ConvertToBitmap") );
+ wxCHECK_MSG( pbmi, 0, wxT("invalid DIB in ConvertToBitmap") );
// here we get BITMAPINFO struct followed by the actual bitmap bits and
// BITMAPINFO starts with BITMAPINFOHEADER followed by colour info
if ( !bits )
{
// we must skip over the colour table to get to the image data
-
- // biClrUsed has the number of colors but it may be not initialized at
- // all
- int numColors = pbmih->biClrUsed;
- if ( !numColors )
+ //
+ // colour table either has the real colour data in which case its
+ // number of entries is given by biClrUsed or is used for masks to be
+ // used for extracting colour information from true colour bitmaps in
+ // which case it always have exactly 3 DWORDs
+ int numColors;
+ switch ( pbmih->biCompression )
{
- numColors = wxGetNumOfBitmapColors(pbmih->biBitCount);
+ case BI_BITFIELDS:
+ numColors = 3;
+ break;
+
+ case BI_RGB:
+ // biClrUsed has the number of colors but it may be not initialized at
+ // all
+ numColors = pbmih->biClrUsed;
+ if ( !numColors )
+ {
+ numColors = GetNumberOfColours(pbmih->biBitCount);
+ }
+ break;
+
+ default:
+ // no idea how it should be calculated for the other cases
+ numColors = 0;
}
bits = (char *)pbmih + sizeof(*pbmih) + numColors*sizeof(RGBQUAD);
bi.biBitCount = bm.bmBitsPixel;
// memory we need for BITMAPINFO only
- DWORD dwLen = bi.biSize + wxGetNumOfBitmapColors(bm.bmBitsPixel) * sizeof(RGBQUAD);
+ DWORD dwLen = bi.biSize + GetNumberOfColours(bm.bmBitsPixel) * sizeof(RGBQUAD);
// get either just the image size or the image bits
if ( !::GetDIBits
{
// this is an error which does risk to happen especially under Win9x
// and which the user may understand so let him know about it
- wxLogError(_("Failed to allocated %luKb of memory for bitmap data."),
+ wxLogError(_("Failed to allocate %luKb of memory for bitmap data."),
(unsigned long)(size / 1024));
return NULL;
}
- if ( !ConvertFromBitmap((BITMAPINFO *)GlobalHandle(hDIB), hbmp) )
+ if ( !ConvertFromBitmap((BITMAPINFO *)(void *)GlobalPtrLock(hDIB), hbmp) )
{
// this really shouldn't happen... it worked the first time, why not
// now?
- wxFAIL_MSG( _T("wxDIB::ConvertFromBitmap() unexpectedly failed") );
+ wxFAIL_MSG( wxT("wxDIB::ConvertFromBitmap() unexpectedly failed") );
return NULL;
}
return hDIB;
}
+#endif // __WXWINCE__
+
// ----------------------------------------------------------------------------
// palette support
// ----------------------------------------------------------------------------
wxPalette *wxDIB::CreatePalette() const
{
- wxCHECK_MSG( m_handle, NULL, _T("wxDIB::CreatePalette(): invalid object") );
+ // GetDIBColorTable not available in eVC3
+#if !defined(__WXMSW__) || defined(_WIN32_WCE) && _WIN32_WCE < 400
+ return NULL;
+#else
+ wxCHECK_MSG( m_handle, NULL, wxT("wxDIB::CreatePalette(): invalid object") );
DIBSECTION ds;
- if ( !::GetObject(m_handle, sizeof(ds), &ds) )
+ if ( !GetDIBSection(m_handle, &ds) )
{
- wxLogLastError(_T("GetObject(hDIB)"));
+ wxLogLastError(wxT("GetObject(hDIB)"));
return 0;
}
if ( !biClrUsed )
{
// biClrUsed field might not be set
- biClrUsed = wxGetNumOfBitmapColors(ds.dsBmih.biBitCount);
+ biClrUsed = GetNumberOfColours(ds.dsBmih.biBitCount);
}
if ( !biClrUsed )
return NULL;
}
+ MemoryHDC hDC;
+
// LOGPALETTE struct has only 1 element in palPalEntry array, we're
// going to have biClrUsed of them so add necessary space
LOGPALETTE *pPalette = (LOGPALETTE *)
malloc(sizeof(LOGPALETTE) + (biClrUsed - 1)*sizeof(PALETTEENTRY));
- wxCHECK_MSG( pPalette, NULL, _T("out of memory") );
+ wxCHECK_MSG( pPalette, NULL, wxT("out of memory") );
// initialize the palette header
pPalette->palVersion = 0x300; // magic number, not in docs but works
- pPalette->palNumEntries = biClrUsed;
+ pPalette->palNumEntries = (WORD)biClrUsed;
- // and the colour table (it starts right after the end of the header)
- const RGBQUAD *pRGB = (RGBQUAD *)((char *)&ds.dsBmih + ds.dsBmih.biSize);
+ // and the colour table
+ wxCharBuffer rgb(sizeof(RGBQUAD) * biClrUsed);
+ RGBQUAD *pRGB = (RGBQUAD*)rgb.data();
+ SelectInHDC selectHandle(hDC, m_handle);
+ ::GetDIBColorTable(hDC, 0, biClrUsed, pRGB);
for ( DWORD i = 0; i < biClrUsed; i++, pRGB++ )
{
pPalette->palPalEntry[i].peRed = pRGB->rgbRed;
if ( !hPalette )
{
- wxLogLastError(_T("CreatePalette"));
+ wxLogLastError(wxT("CreatePalette"));
return NULL;
}
palette->SetHPALETTE((WXHPALETTE)hPalette);
return palette;
+#endif
}
#endif // wxUSE_PALETTE
#if wxUSE_IMAGE
-bool wxDIB::Create(const wxImage& image)
+bool wxDIB::Create(const wxImage& image, PixelFormat pf)
{
- wxCHECK_MSG( image.Ok(), false, _T("invalid wxImage in wxDIB ctor") );
+ wxCHECK_MSG( image.IsOk(), false, wxT("invalid wxImage in wxDIB ctor") );
const int h = image.GetHeight();
const int w = image.GetWidth();
const int srcBytesPerLine = w * 3;
const int dstBytesPerLine = GetLineSize(w, bpp);
const unsigned char *src = image.GetData() + ((h - 1) * srcBytesPerLine);
- const unsigned char *alpha = hasAlpha ? image.GetAlpha() + (h - 1)*w : NULL;
+ const unsigned char *alpha = hasAlpha ? image.GetAlpha() + (h - 1)*w
+ : NULL;
unsigned char *dstLineStart = (unsigned char *)m_data;
for ( int y = 0; y < h; y++ )
{
- // copy one DIB line
+ // Copy one DIB line. Note that RGB components order is reversed in
+ // Windows bitmaps compared to wxImage and is actually BGR.
unsigned char *dst = dstLineStart;
- for ( int x = 0; x < w; x++ )
+ if ( alpha )
{
- // also, the order of RGB is inversed for DIBs
- *dst++ = src[2];
- *dst++ = src[1];
- *dst++ = src[0];
+ int x;
+
+ switch ( pf )
+ {
+ case PixelFormat_PreMultiplied:
+ // Pre-multiply pixel values so that the DIB could be used
+ // with ::AlphaBlend().
+ for ( x = 0; x < w; x++ )
+ {
+ const unsigned char a = *alpha++;
+ *dst++ = (unsigned char)((src[2] * a + 127) / 255);
+ *dst++ = (unsigned char)((src[1] * a + 127) / 255);
+ *dst++ = (unsigned char)((src[0] * a + 127) / 255);
+ *dst++ = a;
+ src += 3;
+ }
+ break;
+
+ case PixelFormat_NotPreMultiplied:
+ // Just copy pixel data without changing it.
+ for ( x = 0; x < w; x++ )
+ {
+ *dst++ = src[2];
+ *dst++ = src[1];
+ *dst++ = src[0];
+
+ *dst++ = *alpha++;
+ src += 3;
+ }
+ break;
+ }
- src += 3;
-
- if ( alpha )
- *dst++ = *alpha++;
+ }
+ else // no alpha channel
+ {
+ for ( int x = 0; x < w; x++ )
+ {
+ *dst++ = src[2];
+ *dst++ = src[1];
+ *dst++ = src[0];
+ src += 3;
+ }
}
// pass to the previous line in the image
return true;
}
+wxImage wxDIB::ConvertToImage() const
+{
+ wxCHECK_MSG( IsOk(), wxNullImage,
+ wxT("can't convert invalid DIB to wxImage") );
+
+ // create the wxImage object
+ const int w = GetWidth();
+ const int h = GetHeight();
+ wxImage image(w, h, false /* don't bother clearing memory */);
+ if ( !image.IsOk() )
+ {
+ wxFAIL_MSG( wxT("could not allocate data for image") );
+ return wxNullImage;
+ }
+
+ const int bpp = GetDepth();
+
+ // Remember if we have any "real" transparency, i.e. either any partially
+ // transparent pixels or not all pixels are fully opaque or fully
+ // transparent.
+ bool hasAlpha = false;
+ bool hasOpaque = false;
+ bool hasTransparent = false;
+
+ if ( bpp == 32 )
+ {
+ // 32 bit bitmaps may be either 0RGB or ARGB and we don't know in
+ // advance which one do we have so suppose we have alpha of them and
+ // get rid of it later if it turns out we didn't.
+ image.SetAlpha();
+ }
+
+ // this is the same loop as in Create() just above but with copy direction
+ // reversed
+ const int dstBytesPerLine = w * 3;
+ const int srcBytesPerLine = GetLineSize(w, bpp);
+ unsigned char *dst = image.GetData() + ((h - 1) * dstBytesPerLine);
+ unsigned char *alpha = image.HasAlpha() ? image.GetAlpha() + (h - 1)*w
+ : NULL;
+ const unsigned char *srcLineStart = (unsigned char *)GetData();
+ for ( int y = 0; y < h; y++ )
+ {
+ // copy one DIB line
+ const unsigned char *src = srcLineStart;
+ for ( int x = 0; x < w; x++ )
+ {
+ dst[2] = *src++;
+ dst[1] = *src++;
+ dst[0] = *src++;
+
+ if ( bpp == 32 )
+ {
+ // wxImage uses non premultiplied alpha so undo
+ // premultiplication done in Create() above
+ const unsigned char a = *src;
+ *alpha++ = a;
+
+ // Check what kind of alpha do we have.
+ switch ( a )
+ {
+ case 0:
+ hasTransparent = true;
+ break;
+
+ default:
+ // Anything in between means we have real transparency
+ // and must use alpha channel.
+ hasAlpha = true;
+ break;
+
+ case 255:
+ hasOpaque = true;
+ break;
+ }
+
+ if ( a > 0 )
+ {
+ dst[0] = (dst[0] * 255) / a;
+ dst[1] = (dst[1] * 255) / a;
+ dst[2] = (dst[2] * 255) / a;
+ }
+
+ src++;
+ }
+
+ dst += 3;
+ }
+
+ // pass to the previous line in the image
+ dst -= 2*dstBytesPerLine;
+ if ( alpha )
+ alpha -= 2*w;
+
+ // and to the next one in the DIB
+ srcLineStart += srcBytesPerLine;
+ }
+
+ if ( hasOpaque && hasTransparent )
+ hasAlpha = true;
+
+ if ( !hasAlpha && image.HasAlpha() )
+ image.ClearAlpha();
+
+ return image;
+}
+
#endif // wxUSE_IMAGE
+#endif // wxUSE_WXDIB
projects / wxWidgets.git / blobdiff