From 4e81da6984774cee4b599265f08e08c1698e8887 Mon Sep 17 00:00:00 2001
From: fvogel <fvogelnew1@free.fr>
Date: Sat, 29 Dec 2018 21:42:12 +0000
Subject: Fix [21525158b0]: On MS Windows XImage data and Tk_Visual() return
 wrong information. Bug report, analysis and patch provided by Scott Pitcher
 (many thanks!)

---
 generic/tkCanvas.c |  2 +-
 win/tkWinDraw.c    | 18 ++++++++++++++++++
 win/tkWinX.c       | 18 ++++++++++++++++++
 3 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/generic/tkCanvas.c b/generic/tkCanvas.c
index 2f45399..53bfe00 100644
--- a/generic/tkCanvas.c
+++ b/generic/tkCanvas.c
@@ -2777,7 +2777,7 @@ DrawCanvas(
              * swap anything here.
              */
 
-#ifdef _WIN32
+#if defined(NO_WINRGBFIX) && defined(_WIN32)
 #define   R_OFFSET 2
 #define   B_OFFSET 0
 #else
diff --git a/win/tkWinDraw.c b/win/tkWinDraw.c
index 2c35d3b..0ec63dc 100644
--- a/win/tkWinDraw.c
+++ b/win/tkWinDraw.c
@@ -519,6 +519,9 @@ TkPutImage(
     BITMAPINFO *infoPtr;
     HBITMAP bitmap;
     char *data;
+#ifndef NO_WINRGBFIX
+    Visual *visual;
+#endif
 
     display->request++;
 
@@ -564,13 +567,18 @@ TkPutImage(
 	infoPtr->bmiHeader.biHeight = -image->height; /* Top-down order */
 	infoPtr->bmiHeader.biPlanes = 1;
 	infoPtr->bmiHeader.biBitCount = image->bits_per_pixel;
+#ifdef NO_WINRGBFIX
 	infoPtr->bmiHeader.biCompression = BI_RGB;
+#endif
 	infoPtr->bmiHeader.biSizeImage = 0;
 	infoPtr->bmiHeader.biXPelsPerMeter = 0;
 	infoPtr->bmiHeader.biYPelsPerMeter = 0;
 	infoPtr->bmiHeader.biClrImportant = 0;
 
 	if (usePalette) {
+#ifndef NO_WINRGBFIX
+	    infoPtr->bmiHeader.biCompression = BI_RGB;
+#endif
 	    infoPtr->bmiHeader.biClrUsed = ncolors;
 	    for (i = 0; i < ncolors; i++) {
 		infoPtr->bmiColors[i].rgbBlue = GetBValue(colors[i]);
@@ -579,7 +587,17 @@ TkPutImage(
 		infoPtr->bmiColors[i].rgbReserved = 0;
 	    }
 	} else {
+#ifdef NO_WINRGBFIX
 	    infoPtr->bmiHeader.biClrUsed = 0;
+#else
+	    infoPtr->bmiHeader.biCompression = BI_BITFIELDS;
+	    /* Modelled on XGetVisualInfo() in xutil.c.
+	     * We want to get the rgb masks for the default visual for the given display. */
+	    visual = DefaultVisual(display,0);
+	    *((DWORD *)((unsigned char *)infoPtr + sizeof(BITMAPINFOHEADER))) = visual->blue_mask;
+	    *((DWORD *)((unsigned char *)infoPtr + sizeof(BITMAPINFOHEADER))+1) = visual->green_mask;
+	    *((DWORD *)((unsigned char *)infoPtr + sizeof(BITMAPINFOHEADER))+2) = visual->red_mask;
+#endif
 	}
 	bitmap = CreateDIBitmap(dc, &infoPtr->bmiHeader, CBM_INIT,
 		image->data, infoPtr, DIB_RGB_COLORS);
diff --git a/win/tkWinX.c b/win/tkWinX.c
index 761d9ca..d010be2 100644
--- a/win/tkWinX.c
+++ b/win/tkWinX.c
@@ -457,21 +457,39 @@ TkWinDisplayChanged(
     } else if (screen->root_depth == 12) {
 	screen->root_visual->class = TrueColor;
 	screen->root_visual->map_entries = 32;
+#ifdef NO_WINRGBFIX
 	screen->root_visual->red_mask = 0xf0;
 	screen->root_visual->green_mask = 0xf000;
 	screen->root_visual->blue_mask = 0xf00000;
+#else
+	screen->root_visual->red_mask = 0xf00000;
+	screen->root_visual->green_mask = 0xf000;
+	screen->root_visual->blue_mask = 0xf0;
+#endif
     } else if (screen->root_depth == 16) {
 	screen->root_visual->class = TrueColor;
 	screen->root_visual->map_entries = 64;
+#ifdef NO_WINRGBFIX
 	screen->root_visual->red_mask = 0xf8;
 	screen->root_visual->green_mask = 0xfc00;
 	screen->root_visual->blue_mask = 0xf80000;
+#else
+	screen->root_visual->red_mask = 0xf80000;
+	screen->root_visual->green_mask = 0xfc00;
+	screen->root_visual->blue_mask = 0xf8;
+#endif
     } else if (screen->root_depth >= 24) {
 	screen->root_visual->class = TrueColor;
 	screen->root_visual->map_entries = 256;
+#ifdef NO_WINRGBFIX
 	screen->root_visual->red_mask = 0xff;
 	screen->root_visual->green_mask = 0xff00;
 	screen->root_visual->blue_mask = 0xff0000;
+#else
+	screen->root_visual->red_mask = 0xff0000;
+	screen->root_visual->green_mask = 0xff00;
+	screen->root_visual->blue_mask = 0xff;
+#endif
     }
     screen->root_visual->bits_per_rgb = screen->root_depth;
     ReleaseDC(NULL, dc);
-- 
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