Add selectionbg-alpha patch (#188)

README.md

@@ -15,6 +15,8 @@ Refer to [https://st.suckless.org/](https://st.suckless.org/) for details on the
 
 ### Changelog:
 
+2025-10-28 - Added the selectionbg-alpha patch
+
 2025-02-20 - Added the drag-n-drop and open-selected-text patches
 
 2024-05-31 - Added the anygeometry patch
@@ -260,6 +262,10 @@ Refer to [https://st.suckless.org/](https://st.suckless.org/) for details on the
    - [right-click-to-plumb](https://st.suckless.org/patches/right_click_to_plumb/)
       - allows you to right-click on some selected text to send it to the plumbing program of choice
 
+   - [selectionbg-alpha](https://st.suckless.org/patches/selectionbg-alpha/)
+      - allows for the selection to have a transparent background when combined with the alpha
+        and selection colors patches
+
    - [scrollback](https://st.suckless.org/patches/scrollback/)
       - allows you scroll back through terminal output using keyboard shortcuts or mousewheel
 

patches.def.h

@@ -380,6 +380,12 @@
  */
 #define SELECTION_COLORS_PATCH 0
 
+/* This patch works with selectioncolors and alpha patches to make selection
+ * background color transparent.
+ * https://st.suckless.org/patches/selectionbg-alpha/
+ */
+#define SELECTIONBG_ALPHA_PATCH 0
+
 /* This is the single drawable buffer patch as outlined in the FAQ to get images
  * in w3m to display. While this patch does not break the alpha patch it images
  * are not shown in w3m if the alpha patch is applied.

x.c

@@ -980,6 +980,11 @@ xloadalpha(void)
 	dc.col[defaultbg].color.alpha = (unsigned short)(0xffff * usedAlpha);
 	dc.col[defaultbg].pixel &= 0x00FFFFFF;
 	dc.col[defaultbg].pixel |= (unsigned char)(0xff * usedAlpha) << 24;
+	#if SELECTION_COLORS_PATCH && SELECTIONBG_ALPHA_PATCH
+	dc.col[selectionbg].color.alpha = (unsigned short)(0xffff * usedAlpha);
+	dc.col[selectionbg].pixel &= 0x00FFFFFF;
+	dc.col[selectionbg].pixel |= (unsigned char)(0xff * usedAlpha) << 24;
+	#endif // SELECTION_COLORS_PATCH && SELECTIONBG_ALPHA_PATCH
 }
 #endif // ALPHA_FOCUS_HIGHLIGHT_PATCH
 
@@ -1041,6 +1046,18 @@ xloadcols(void)
 	dc.col[defaultbg].color.red   *= alpha;
 	dc.col[defaultbg].color.green *= alpha;
 	dc.col[defaultbg].color.blue  *= alpha;
+	#if SELECTION_COLORS_PATCH && SELECTIONBG_ALPHA_PATCH
+	/* set alpha value of selbg color */
+	dc.col[selectionbg].color.alpha = (unsigned short)(0xffff * alpha);
+	dc.col[selectionbg].pixel &= 0x00FFFFFF;
+	dc.col[selectionbg].pixel |= (unsigned char)(0xff * alpha) << 24;
+	dc.col[selectionbg].color.red =
+		((unsigned short)(dc.col[selectionbg].color.red * alpha)) & 0xff00;
+	dc.col[selectionbg].color.green =
+		((unsigned short)(dc.col[selectionbg].color.green * alpha)) & 0xff00;
+	dc.col[selectionbg].color.blue =
+		((unsigned short)(dc.col[selectionbg].color.blue * alpha)) & 0xff00;
+	#endif // SELECTION_COLORS_PATCH && SELECTIONBG_ALPHA_PATCH
 	#endif // ALPHA_PATCH
 	loaded = 1;
 }