initial commit

Signed-off-by: Peter Siegmund <mars3142@noreply.mars3142.dev>

libs/wxWidgets-3.3.1/include/wx/msw/private/custompaint.h

@@ -0,0 +1,82 @@
+///////////////////////////////////////////////////////////////////////////////
+// Name:        wx/msw/private/custompaint.h
+// Purpose:     Helper function for customizing the standard WM_PAINT handling.
+// Author:      Vadim Zeitlin
+// Created:     2023-06-02
+// Copyright:   (c) 2023 Vadim Zeitlin <vadim@wxwidgets.org>
+// Licence:     wxWindows licence
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef _WX_MSW_PRIVATE_CUSTOMPAINT_H_
+#define _WX_MSW_PRIVATE_CUSTOMPAINT_H_
+
+#include "wx/dcmemory.h"
+#include "wx/image.h"
+
+#include "wx/msw/dc.h"
+
+namespace wxMSWImpl
+{
+
+// This function can be used as CustomPaint() callback to post process the
+// bitmap by applying the specific functor to each of its pixels.
+template <typename FuncProcessPixel>
+wxBitmap
+PostPaintEachPixel(const wxBitmap& bmp, FuncProcessPixel processPixel)
+{
+#if wxUSE_IMAGE
+    wxImage image = bmp.ConvertToImage();
+
+    unsigned char *data = image.GetData();
+    unsigned char *alpha = image.GetAlpha();
+    unsigned char alphaOpaque = wxALPHA_OPAQUE;
+    const int len = image.GetWidth()*image.GetHeight();
+    for ( int i = 0; i < len; ++i, data += 3 )
+    {
+        processPixel(data[0], data[1], data[2], alpha ? *alpha++ : alphaOpaque);
+    }
+
+    return wxBitmap(image);
+#else // !wxUSE_IMAGE
+    return bmp;
+#endif // wxUSE_IMAGE/!wxUSE_IMAGE
+}
+
+// This function uses the default WM_PAINT handler to paint the window contents
+// into a bitmap and then the provided function to tweak the pixels of this
+// bitmap.
+//
+// The first argument is a functor (typically a lambda) to paint the on the
+// given HDC and the second one is another functor called to post process the
+// bitmap before actually drawing it.
+//
+// It can only be called from WM_PAINT handler for a native control and assumes
+// that this control handles WPARAM argument of WM_PAINT as HDC to paint on.
+template <typename FuncDefPaint, typename FuncPostProcess>
+void
+CustomPaint(HWND hwnd, FuncDefPaint defPaint, FuncPostProcess postProcess)
+{
+    const RECT rc = wxGetClientRect(hwnd);
+    const wxSize size{rc.right - rc.left, rc.bottom - rc.top};
+
+    // Don't bother doing anything with the empty windows.
+    if ( size == wxSize() )
+        return;
+
+    // Ask the control to paint itself on the given bitmap.
+    wxBitmap bmp(size);
+    {
+        wxMemoryDC mdc(bmp);
+
+        defPaint(hwnd, (WPARAM)GetHdcOf(mdc));
+    }
+
+    PAINTSTRUCT ps;
+    wxDCTemp dc(::BeginPaint(hwnd, &ps), size);
+    dc.DrawBitmap(postProcess(bmp), 0, 0);
+    ::EndPaint(hwnd, &ps);
+}
+
+} // namespace wxMSWImpl
+
+#endif // _WX_MSW_PRIVATE_CUSTOMPAINT_H_