SCROLLREGION

Author: braindigitalis

include/basic/console.h

@@ -131,6 +131,14 @@ int64_t basic_capslock(struct basic_ctx* ctx);
  */
 void input_statement(struct basic_ctx* ctx);
 
+
+/**
+ * @brief Handle SCROLLREGION statement.
+ *
+ * @param ctx The BASIC context.
+ */
+void scrollregion_statement(struct basic_ctx* ctx);
+
 /**
  * @brief Process GET statement to read a single keypress.
  *

include/basic/tokenizer.h

@@ -202,6 +202,7 @@ typedef void (*keyword_handler_t)(struct basic_ctx*);
     T(UNLOAD, STMT, NULL) 				/* 130 */ \
     T(ENVELOPE, STMT, envelope_statement)		/* 131 */ \
     T(TONE, STMT, NULL) 				/* 132 */ \
+    T(SCROLLREGION, STMT, scrollregion_statement)	/* 133 */ \
 
 GENERATE_ENUM_LIST(TOKEN, token_t)
 

include/flanterm.h

@@ -42,6 +42,7 @@ extern "C" {
 #define FLANTERM_CB_KBD_LEDS 60
 #define FLANTERM_CB_MODE 70
 #define FLANTERM_CB_LINUX 80
+#define FLANTERM_CB_SCROLL 90
 
 #define FLANTERM_OOB_OUTPUT_OCRNL (1 << 0)
 #define FLANTERM_OOB_OUTPUT_OFDEL (1 << 1)

include/video.h

@@ -256,4 +256,6 @@ unsigned char map_vga_to_ansi_bg(unsigned char colour);
 
 void redefine_character(unsigned char c, uint8_t bitmap[8]);
 
-void graphics_putstring(const char *s, int64_t x, int64_t y, int32_t colour);
+void graphics_putstring(const char *s, int64_t x, int64_t y, int32_t colour);
+
+int add_scrollable(int64_t start, int64_t end);

os/programs/about.rrbasic

@@ -1,51 +1,75 @@
+REM Retro Rocket "about" program.
+REM
+REM Similar to "neofetch".
+REM Be careful about where you write characters in the space where you
+REM plot the rocky PNG and colour palette spectrum. If you write a blank
+REM line anywhere, it will manifest as a vertical bar across the image
+REM when you scroll due to the way flanterm is optimised
+REM
 SPRITELOAD owl,"/images/owl.png"
 AUTOFLIP FALSE
-REM Go down 20 lines, then back up, to make room on screen for the images
-FOR Y = 0 TO 19
-    PRINT ""
+REM Go down 25 lines, then back up, to make room on screen for the images
+FOR Y = 0 TO 24
+    PRINT " "
 NEXT
-CURSOR 0, CURRENTY - 19
+CURSOR 0, CURRENTY - 24
+STARTY=CURRENTY
 SPRTOP=CURRENTY*8
 COLOUR 14
-PRINT "                                  Retro Rocket"
+Y=CURRENTY
+CURSOR 34,Y
+PRINT "Retro Rocket";
 COLOUR 7
-PRINT "                                  ────────────"
+Y = Y + 1
+CURSOR 34,Y
+PRINT "────────────";
 COLOUR 14
-PRINT "                                  OS: ";
+Y = Y + 1
+CURSOR 34,Y
+PRINT "OS: ";
 COLOUR 7
-PRINT "Retro Rocket 1.0"
+PRINT "Retro Rocket 1.0";
 COLOUR 14
-PRINT "                                  Kernel: ";
+Y = Y + 1
+CURSOR 34,Y
+PRINT "Kernel: ";
 COLOUR 7
-PRINT "1.0"
+PRINT "1.0";
 COLOUR 14
-PRINT "                                  Uptime: ";
+Y = Y + 1
+CURSOR 34,Y
+PRINT "Uptime: ";
 COLOUR 7
-PRINT UPTIME$
+PRINT UPTIME$;
 COLOUR 14
-PRINT "                                  Shell: ";
+Y = Y + 1
+CURSOR 34,Y
+PRINT "Shell: ";
 COLOUR 7
-PRINT "rocketsh-2.0"
+PRINT "rocketsh-2.0";
 COLOUR 14
-PRINT "                                  Memory: ";
+Y = Y + 1
+CURSOR 34,Y
+PRINT "Memory: ";
 COLOUR 7
 M_MEGS = MEMUSED / 1024 / 1024
 MT_MEGS = MEMORY / 1024 / 1024
-PRINT M_MEGS; "MiB / "; MT_MEGS ; "MiB"
+PRINT M_MEGS; "MiB / "; MT_MEGS ; "MiB";
 COLOUR 14
-PRINT "                                  Resolution: ";
+Y = Y + 1
+CURSOR 34,Y
+PRINT "Resolution: ";
 COLOUR 7
-PRINT GRAPHICS_WIDTH; "x"; GRAPHICS_HEIGHT
+PRINT GRAPHICS_WIDTH; "x"; GRAPHICS_HEIGHT;
 COLOUR 14
-PRINT "                                  CPU: ";
+Y = Y + 1
+CURSOR 34,Y
+PRINT "CPU: ";
 COLOUR 7
-PRINT CPUGETBRAND$(1)
-PRINT "                                  ";
-GRADLEFT=CURRENTX*8
-GRADTOP=CURRENTY*8+8
-FOR N = 0 TO 14
-    PRINT ""
-NEXT
+PRINT CPUGETBRAND$(1);
+GRADLEFT=34*8
+GRADTOP=CURRENTY*8+16
+CURSOR 0, CURRENTY + 17
 PLOT owl,32,SPRTOP
 X = GRADLEFT
 W = 128
@@ -88,4 +112,7 @@ FOR I = 0 TO W - 1
   LINE X, GRADTOP, X, GRADTOP + H
   X = X + 1
 NEXT
-AUTOFLIP TRUE
+AUTOFLIP TRUE
+PRINT "                                                   "
+ENDY=CURRENTY
+SCROLLREGION STARTY, ENDY - 1

src/basic/console.c

@@ -139,8 +139,7 @@ void cls_statement(struct basic_ctx* ctx)
 	accept_or_return(NEWLINE, ctx);
 }
 
-void gotoxy_statement(struct basic_ctx* ctx)
-{
+void gotoxy_statement(struct basic_ctx* ctx) {
 	accept_or_return(CURSOR, ctx);
 	int64_t x = expr(ctx);
 	accept_or_return(COMMA, ctx);
@@ -149,6 +148,15 @@ void gotoxy_statement(struct basic_ctx* ctx)
 	accept_or_return(NEWLINE, ctx);
 }
 
+void scrollregion_statement(struct basic_ctx* ctx) {
+	accept_or_return(SCROLLREGION, ctx);
+	int64_t top = expr(ctx) * 8;
+	accept_or_return(COMMA, ctx);
+	int64_t bottom = expr(ctx) * 8 + 8;
+	add_scrollable(top, bottom);
+	accept_or_return(NEWLINE, ctx);
+}
+
 void print_statement(struct basic_ctx* ctx) {
 	accept_or_return(PRINT, ctx);
 	const char* out = printable_syntax(ctx);

src/flanterm/fb.c

@@ -263,8 +263,7 @@ static void flanterm_fb_revscroll(struct flanterm_context *_ctx) {
 static void flanterm_fb_scroll(struct flanterm_context *_ctx) {
 	struct flanterm_fb_context *ctx = (void *) _ctx;
 
-	for (size_t i = (_ctx->scroll_top_margin + 1) * _ctx->cols;
-	     i < _ctx->scroll_bottom_margin * _ctx->cols; i++) {
+	for (size_t i = (_ctx->scroll_top_margin + 1) * _ctx->cols; i < _ctx->scroll_bottom_margin * _ctx->cols; i++) {
 		struct flanterm_fb_char *c;
 		struct flanterm_fb_queue_item *q = ctx->map[i];
 		if (q != NULL) {
@@ -283,6 +282,10 @@ static void flanterm_fb_scroll(struct flanterm_context *_ctx) {
 	for (size_t i = 0; i < _ctx->cols; i++) {
 		push_to_queue(_ctx, &empty, i, _ctx->scroll_bottom_margin - 1);
 	}
+
+	if (_ctx->callback != NULL) {
+		_ctx->callback(_ctx, FLANTERM_CB_SCROLL, 0, 0, 0);
+	}
 }
 
 static void flanterm_fb_clear(struct flanterm_context *_ctx, bool move) {

src/video.c

@@ -7,6 +7,17 @@ volatile struct limine_framebuffer_request framebuffer_request = {
 	.revision = 0,
 };
 
+
+#define MAX_SCROLLABLES 256
+
+typedef struct scrollable_graphics_t {
+	int64_t start;
+	int64_t end;
+} scrollable_graphics_t;
+
+static scrollable_graphics_t scrollables[MAX_SCROLLABLES];
+static int scrollable_count = 0;
+
 struct limine_framebuffer *fb = NULL;
 static uint64_t bytes_per_pixel = 32;
 static void *rr_fb_front = NULL;
@@ -91,6 +102,45 @@ static uint8_t font_data[]  = { // 8x8
 	0x00, 0x2e, 0x33, 0x33, 0x33, 0x00, 0x00, 0x00, 0x38, 0x08, 0x38, 0x20, 0x38, 0x00, 0x00, 0x00, 0x00, 0x18, 0x18, 0x18, 0x18, 0x18, 0x18, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 };
 
+
+/* Insert a band [start, end), keeping the list sorted by start */
+int add_scrollable(int64_t start, int64_t end) {
+	if (scrollable_count >= MAX_SCROLLABLES) {
+		return -1; /* list full */
+	}
+
+	int pos = 0;
+	while (pos < scrollable_count && scrollables[pos].start < start) {
+		pos++;
+	}
+
+	/* shift up to make room */
+	for (int i = scrollable_count; i > pos; i--) {
+		scrollables[i] = scrollables[i - 1];
+	}
+
+	scrollables[pos].start = start;
+	scrollables[pos].end = end;
+	scrollable_count++;
+
+	return 0;
+}
+
+/* Remove a band matching [start, end) */
+int remove_scrollable(int64_t start, int64_t end) {
+	for (int i = 0; i < scrollable_count; i++) {
+		if (scrollables[i].start == start && scrollables[i].end == end) {
+			/* shift down */
+			for (int j = i; j < scrollable_count - 1; j++) {
+				scrollables[j] = scrollables[j + 1];
+			}
+			scrollable_count--;
+			return 0;
+		}
+	}
+	return -1; /* not found */
+}
+
 void rr_console_init_from_limine(void) {
 	fb = framebuffer_request.response->framebuffers[0];
 	dprintf("fb front: %lx\n", (uint64_t)fb->address);
@@ -218,11 +268,78 @@ void terminal_callback(struct flanterm_context *ctx, uint64_t type, uint64_t x,
 	switch (type) {
 		case FLANTERM_CB_BELL:
 			beep(1000);
-		break;
+			break;
 		case FLANTERM_CB_POS_REPORT:
 			current_x = x - 1;
 			current_y = y - 1;
-		break;
+			break;
+		case FLANTERM_CB_SCROLL: {
+			int stride   = rr_fb_pitch;
+			int delta_px = 8;
+			bool moved = false;
+
+			for (int i = 0; i < scrollable_count;) {
+				if (scrollable_count == 0) {
+					break;
+				}
+
+				scrollable_graphics_t *s = &scrollables[i];
+				int height = (int)(s->end - s->start);
+
+				if (height <= 0) {
+					/* drop invalid band */
+					for (int j = i; j < scrollable_count - 1; j++) {
+						scrollables[j] = scrollables[j + 1];
+					}
+					scrollable_count--;
+					continue;
+				}
+
+				int new_start = s->start - delta_px;
+				int new_end   = s->end   - delta_px;
+
+				int dst_row = new_start;
+				int src_row = s->start;
+				int rows    = height;
+
+				/* trim off rows above the top */
+				if (dst_row < 0) {
+					int cut = -dst_row;
+					dst_row = 0;
+					src_row += cut;
+					rows    -= cut;
+				}
+
+				/* trim if bottom goes past screen (end is exclusive) */
+				if (dst_row + rows > screen_graphics_y) {
+					rows = screen_graphics_y - dst_row;
+				}
+
+				if (rows > 0) {
+					uint8_t *dst = (uint8_t *)rr_fb_back + (long)dst_row * stride;
+					uint8_t *src = (uint8_t *)rr_fb_back + (long)src_row * stride;
+					memmove(dst, src, (size_t)rows * stride);
+					moved = true;
+				}
+
+				s->start = new_start;
+				s->end   = new_end;
+
+				if (s->end <= 0 || s->start >= screen_graphics_y) {
+					for (int j = i; j < scrollable_count - 1; j++) {
+						scrollables[j] = scrollables[j + 1];
+					}
+					scrollable_count--;
+					continue;
+				}
+
+				i++;
+			}
+			if (moved) {
+				set_video_dirty_area(0, screen_graphics_y);
+			}
+			break;
+		}
 	}
 	wait_state = false;
 }