Re: Stipples support in MS-Windows port

["Elijah G." <eg642616@gmail.com>]

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Good news, the stipple implementation is now done, now works using
indent-bars package and other stipples, however there are some
issues that i want to remark

1. Currently it only works for stipple data and not for X Bitmap files,
   I don't know where is stored the code for using X Bitmap in stipples.

2. I had to use `w32_create_pixmap_from_bitmap_data` for make it usable,
   but it is defined before `image_create_bitmap_from_data`, i had to
   copy its code for use it, Is there a problem move that function
   before `image_create_bitmap_from_data` ?

3. The bitmap created using the copied code have colors inverted,
   I fixed it setting text color to background color and bg to fg color,
   I'm not sure how w32_create_pixmap_from_bitmap_data works, as far as
   i could see it does some operations to the memory, something that i
   don't think i can help so much.

After fixing 1 (and maybe 2), I will only need to format the code (and
maybe rename XFillRectangle function) for send the final patch here.

I'm attaching the work done if you all want to test it.

Thanks.


[-- Attachment #2: Test using indent-bars package --]
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[-- Attachment #3: 0001-WIP-Stipple-implementation-for-MS-Windows.patch --]
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From f5dd217c5d7ae9d2aae9c18247d5d954fa170bf6 Mon Sep 17 00:00:00 2001
From: "Elias G. Perez" <eg642616@gmail.com>
Date: Fri, 10 May 2024 20:36:42 -0600
Subject: [PATCH] [WIP] Stipple implementation for MS Windows

---
 src/image.c   | 32 +++++++++++++++++++++++++++++++-
 src/w32term.c | 38 ++++++++++++++++++++++++++++++++------
 src/w32term.h |  1 +
 3 files changed, 64 insertions(+), 7 deletions(-)

diff --git a/src/image.c b/src/image.c
index e93fc3183af..95da8353787 100644
--- a/src/image.c
+++ b/src/image.c
@@ -602,7 +602,36 @@ image_create_bitmap_from_data (struct frame *f, char *bits,
 			 FRAME_DISPLAY_INFO (XFRAME (frame))->n_planes,
 			 FRAME_DISPLAY_INFO (XFRAME (frame))->n_cbits,
 			 bits);
-  if (! bitmap)
+  Emacs_Pixmap stipple;
+
+  /* code extracted from `w32_create_pixmap_from_bitmap_data` */
+
+  static unsigned char swap_nibble[16]
+    = { 0x0, 0x8, 0x4, 0xc,    /* 0000 1000 0100 1100 */
+        0x2, 0xa, 0x6, 0xe,    /* 0010 1010 0110 1110 */
+        0x1, 0x9, 0x5, 0xd,    /* 0001 1001 0101 1101 */
+        0x3, 0xb, 0x7, 0xf };  /* 0011 1011 0111 1111 */
+  int i, j, w1, w2;
+  unsigned char *data, *p;
+
+  w1 = (width + 7) / 8;         /* nb of 8bits elt in X bitmap */
+  w2 = ((width + 15) / 16) * 2; /* nb of 16bits elt in W32 bitmap */
+  data = alloca (height * w2);
+  memset (data, 0, height * w2);
+  for (i = 0; i < height; i++)
+    {
+      p = data + i*w2;
+      for (j = 0; j < w1; j++)
+	{
+	  /* Bitswap XBM bytes to match how Windows does things.  */
+	  unsigned char c = *bits++;
+	  *p++ = (unsigned char)((swap_nibble[c & 0xf] << 4)
+				 | (swap_nibble[(c>>4) & 0xf]));
+	}
+    }
+  stipple = CreateBitmap (width, height, 1, 1, (char *) data);
+
+  if (!bitmap || !stipple)
     return -1;
 #endif /* HAVE_NTGUI */
 
@@ -681,6 +710,7 @@ image_create_bitmap_from_data (struct frame *f, char *bits,
 
 #ifdef HAVE_NTGUI
   dpyinfo->bitmaps[id - 1].pixmap = bitmap;
+  dpyinfo->bitmaps[id - 1].stipple = stipple;
   dpyinfo->bitmaps[id - 1].hinst = NULL;
   dpyinfo->bitmaps[id - 1].depth = 1;
 #endif /* HAVE_NTGUI */
diff --git a/src/w32term.c b/src/w32term.c
index a9aff304771..c72870e0b67 100644
--- a/src/w32term.c
+++ b/src/w32term.c
@@ -1248,6 +1248,33 @@ w32_clear_glyph_string_rect (struct glyph_string *s,
                  real_w, real_h);
 }
 
+/* Fill background with bitmap S glyph, with GC, X, Y, WIDTH, HEIGHT, HDC. */
+static void
+XFillRectangle (HDC hdc, struct glyph_string *s, Emacs_GC *gc,
+		int x, int y, unsigned int width, unsigned int height)
+{
+  /* NOTE: stipple bitmap has the inverted colors, inverting those 2
+   * functions color must fix this. */
+  SetTextColor (hdc, gc->background);
+  SetBkColor (hdc, gc->foreground);
+
+  Emacs_Pixmap bm;
+  HBRUSH hb;
+
+  bm = FRAME_DISPLAY_INFO (s->f)->bitmaps[s->face->stipple - 1].stipple;
+  hb = CreatePatternBrush (bm);
+
+  /* Is this part below written correctly? */
+  RECT r;
+  r.left = x;
+  r.top = y;
+  r.right = x + width + 1;
+  r.bottom = y + height + 1;
+
+  FillRect (hdc, &r, hb);
+
+  DeleteObject (hb);
+}
 
 /* Draw the background of glyph_string S.  If S->background_filled_p
    is non-zero don't draw it.  FORCE_P non-zero means draw the
@@ -1264,16 +1291,15 @@ w32_draw_glyph_string_background (struct glyph_string *s, bool force_p)
     {
       int box_line_width = max (s->face->box_horizontal_line_width, 0);
 
-#if 0 /* TODO: stipple */
+#if 1 /* TODO: stipple */
       if (s->stippled_p)
 	{
 	  /* Fill background with a stipple pattern.  */
-	  XSetFillStyle (s->display, s->gc, FillOpaqueStippled);
-	  XFillRectangle (s->display, FRAME_W32_WINDOW (s->f), s->gc, s->x,
-			  s->y + box_line_width,
-			  s->background_width,
+	  /* XSetFillStyle (s->display, s->gc, FillOpaqueStippled); */
+	  XFillRectangle (s->hdc, s, s->gc, s->x,
+			  s->y + box_line_width, s->background_width,
 			  s->height - 2 * box_line_width);
-	  XSetFillStyle (s->display, s->gc, FillSolid);
+	  /* XSetFillStyle (s->display, s->gc, FillSolid); */
 	  s->background_filled_p = true;
 	}
       else
diff --git a/src/w32term.h b/src/w32term.h
index 3120c8bd71f..1eb6a660248 100644
--- a/src/w32term.h
+++ b/src/w32term.h
@@ -58,6 +58,7 @@ #define CP_DEFAULT 1004
 {
   Emacs_Pixmap pixmap;
   char *file;
+  Emacs_Pixmap stipple;
   HINSTANCE hinst; /* Used to load the file */
   int refcount;
   /* Record some info about this pixmap.  */
-- 
2.44.0.windows.1