From 990f7710c892b2fe8690d5a28ccb35137e58934e Mon Sep 17 00:00:00 2001
From: P. J. McDermott <pj@pehjota.net>
Date: Fri, 19 Mar 2021 10:14:30 -0400
Subject: help: Draw scrollbar triangles

---
diff --git a/src/help.c b/src/help.c
index dc5c071..60bcdb7 100644
--- a/src/help.c
+++ b/src/help.c
@@ -56,6 +56,31 @@ const char *_db_help_text =
 	"they bounce off walls in the opposite direction.  To stop, move "
 	"against a wall.";
 
+static void
+_db_help_triangle(SDL_Renderer *renderer, Uint8 r, Uint8 g, Uint8 b, Uint8 a,
+		int x_min, int y_min, int dir)
+{
+	int       i;
+	int       y;
+	int       x;
+	SDL_Point points[(16 * (16 + 2)) / 4];
+
+	i = 0;
+	for (y = 0; y < (16 / 2); ++y) {
+		for (x = y; x < (16 - y); ++x) {
+			points[i].x = x_min + x;
+			if (dir > 0) {
+				points[i].y = y_min + y;
+			} else {
+				points[i].y = y_min + (16 / 2) - 1 - y;
+			}
+			++i;
+		}
+	}
+	SDL_SetRenderDrawColor(renderer, r, g, b, a);
+	SDL_RenderDrawPoints(renderer, points, i);
+}
+
 void
 db_help(void)
 {
@@ -65,7 +90,8 @@ db_help(void)
 	SDL_Color     color;
 	SDL_Surface  *surface;
 	SDL_Texture  *texture;
-	SDL_Rect      dest_rect;
+	SDL_Rect      text_src_rect;
+	SDL_Rect      text_dst_rect;
 
 	font_path = db_strcat(db_get_fonts_dir(), "/UbuntuTitling-Bold.ttf");
 
@@ -84,7 +110,7 @@ db_help(void)
 	color.a = 0xFF;
 
 	surface = TTF_RenderText_Blended_Wrapped(font, _db_help_text, color,
-			608);
+			592);
 	if (surface == NULL) {
 		db_err("Failed to create surface (%s)", TTF_GetError());
 		return;
@@ -96,13 +122,20 @@ db_help(void)
 		return;
 	}
 
-	dest_rect.x = 16;
-	dest_rect.y = 16;
-	dest_rect.w = surface->w;
-	dest_rect.h = surface->h;
+	text_src_rect.x =   0;
+	text_src_rect.y =   0;
+	text_src_rect.w = 592;
+	text_src_rect.h = 448;
+
+	text_dst_rect.x =  16;
+	text_dst_rect.y =  16;
+	text_dst_rect.w = 592;
+	text_dst_rect.h = 448;
 
 	SDL_RenderClear(renderer);
-	SDL_RenderCopy(renderer, texture, NULL, &dest_rect);
+	SDL_RenderCopy(renderer, texture, &text_src_rect, &text_dst_rect);
+	_db_help_triangle(renderer, 0x3F, 0x3F, 0x7F, 0xFF, 608,  16, -1);
+	_db_help_triangle(renderer, 0x00, 0x00, 0xFF, 0xFF, 608, 456,  1);
 	SDL_RenderPresent(renderer);
 	SDL_Delay(1000);
 }
--
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