Add ScrollUp and ScrollDown commands for viewport scrolling, refine mouse wheel handling in GUI and terminal, and bump version to 1.2.2.

CMakeLists.txt

@@ -4,7 +4,7 @@ project(kte)
 include(GNUInstallDirs)
 
 set(CMAKE_CXX_STANDARD 17)
-set(KTE_VERSION "1.2.1")
+set(KTE_VERSION "1.2.2")
 
 # Default to terminal-only build to avoid SDL/OpenGL dependency by default.
 # Enable with -DBUILD_GUI=ON when SDL2/OpenGL/Freetype are available.

Command.cc

@@ -42,12 +42,11 @@ compute_render_x(const std::string &line, const std::size_t curx, const std::siz
 static void
 ensure_cursor_visible(const Editor &ed, Buffer &buf)
 {
-	const std::size_t rows = ed.Rows();
 	const std::size_t cols = ed.Cols();
-	if (rows == 0 || cols == 0)
+	if (cols == 0)
 		return;
 
-	const std::size_t content_rows = rows > 0 ? rows - 1 : 0; // last row = status
+	const std::size_t content_rows = ed.ContentRows();
 	const std::size_t cury         = buf.Cury();
 	const std::size_t curx         = buf.Curx();
 	std::size_t rowoffs            = buf.Rowoffs();
@@ -3004,9 +3003,7 @@ cmd_page_up(CommandContext &ctx)
 	ensure_at_least_one_line(*buf);
 	auto &rows               = buf->Rows();
 	int repeat               = ctx.count > 0 ? ctx.count : 1;
-	std::size_t content_rows = ctx.editor.Rows() > 0 ? ctx.editor.Rows() - 1 : 0;
-	if (content_rows == 0)
-		content_rows = 1;
+	std::size_t content_rows = std::max<std::size_t>(1, ctx.editor.ContentRows());
 
 	// Base on current top-of-screen (row offset)
 	std::size_t rowoffs = buf->Rowoffs();
@@ -3030,7 +3027,6 @@ cmd_page_up(CommandContext &ctx)
 		y = rows.empty() ? 0 : rows.size() - 1;
 	buf->SetOffsets(rowoffs, 0);
 	buf->SetCursor(0, y);
-	ensure_cursor_visible(ctx.editor, *buf);
 	return true;
 }
 
@@ -3046,9 +3042,7 @@ cmd_page_down(CommandContext &ctx)
 	ensure_at_least_one_line(*buf);
 	auto &rows               = buf->Rows();
 	int repeat               = ctx.count > 0 ? ctx.count : 1;
-	std::size_t content_rows = ctx.editor.Rows() > 0 ? ctx.editor.Rows() - 1 : 0;
-	if (content_rows == 0)
-		content_rows = 1;
+	std::size_t content_rows = std::max<std::size_t>(1, ctx.editor.ContentRows());
 
 	std::size_t rowoffs = buf->Rowoffs();
 	// Compute maximum top offset
@@ -3069,7 +3063,74 @@ cmd_page_down(CommandContext &ctx)
 	std::size_t y = std::min<std::size_t>(rowoffs, rows.empty() ? 0 : rows.size() - 1);
 	buf->SetOffsets(rowoffs, 0);
 	buf->SetCursor(0, y);
-	ensure_cursor_visible(ctx.editor, *buf);
+	return true;
+}
+
+
+static bool
+cmd_scroll_up(CommandContext &ctx)
+{
+	Buffer *buf = ctx.editor.CurrentBuffer();
+	if (!buf)
+		return false;
+	ensure_at_least_one_line(*buf);
+	const auto &rows         = buf->Rows();
+	std::size_t content_rows = std::max<std::size_t>(1, ctx.editor.ContentRows());
+	std::size_t rowoffs      = buf->Rowoffs();
+
+	// Scroll up by 3 lines (or count if specified), without moving cursor
+	int scroll_amount = ctx.count > 0 ? ctx.count : 3;
+	if (rowoffs >= static_cast<std::size_t>(scroll_amount))
+		rowoffs -= static_cast<std::size_t>(scroll_amount);
+	else
+		rowoffs = 0;
+
+	buf->SetOffsets(rowoffs, buf->Coloffs());
+
+	// If cursor is now below the visible area, move it to the last visible line
+	std::size_t cury = buf->Cury();
+	if (cury >= rowoffs + content_rows) {
+		std::size_t new_y = rowoffs + content_rows - 1;
+		if (new_y >= rows.size() && !rows.empty())
+			new_y = rows.size() - 1;
+		buf->SetCursor(buf->Curx(), new_y);
+	}
+
+	return true;
+}
+
+
+static bool
+cmd_scroll_down(CommandContext &ctx)
+{
+	Buffer *buf = ctx.editor.CurrentBuffer();
+	if (!buf)
+		return false;
+	ensure_at_least_one_line(*buf);
+	const auto &rows         = buf->Rows();
+	std::size_t content_rows = std::max<std::size_t>(1, ctx.editor.ContentRows());
+	std::size_t rowoffs      = buf->Rowoffs();
+
+	// Scroll down by 3 lines (or count if specified), without moving cursor
+	int scroll_amount = ctx.count > 0 ? ctx.count : 3;
+
+	// Compute maximum top offset
+	std::size_t max_top = 0;
+	if (!rows.empty() && rows.size() > content_rows)
+		max_top = rows.size() - content_rows;
+
+	rowoffs += static_cast<std::size_t>(scroll_amount);
+	if (rowoffs > max_top)
+		rowoffs = max_top;
+
+	buf->SetOffsets(rowoffs, buf->Coloffs());
+
+	// If cursor is now above the visible area, move it to the first visible line
+	std::size_t cury = buf->Cury();
+	if (cury < rowoffs) {
+		buf->SetCursor(buf->Curx(), rowoffs);
+	}
+
 	return true;
 }
 
@@ -3682,6 +3743,8 @@ InstallDefaultCommands()
 	CommandRegistry::Register({CommandId::MoveEnd, "end", "Move to end of line", cmd_move_end});
 	CommandRegistry::Register({CommandId::PageUp, "page-up", "Page up", cmd_page_up});
 	CommandRegistry::Register({CommandId::PageDown, "page-down", "Page down", cmd_page_down});
+	CommandRegistry::Register({CommandId::ScrollUp, "scroll-up", "Scroll viewport up", cmd_scroll_up});
+	CommandRegistry::Register({CommandId::ScrollDown, "scroll-down", "Scroll viewport down", cmd_scroll_down});
 	CommandRegistry::Register({CommandId::WordPrev, "word-prev", "Move to previous word", cmd_word_prev});
 	CommandRegistry::Register({CommandId::WordNext, "word-next", "Move to next word", cmd_word_next});
 	CommandRegistry::Register({

Command.h

@@ -58,6 +58,8 @@ enum class CommandId {
 	MoveEnd,
 	PageUp,
 	PageDown,
+	ScrollUp, // scroll viewport up (towards beginning) without moving cursor
+	ScrollDown, // scroll viewport down (towards end) without moving cursor
 	WordPrev,
 	WordNext,
 	DeleteWordPrev, // delete previous word (ESC BACKSPACE)

Editor.h

@@ -32,6 +32,16 @@ public:
 	}
 
 
+	[[nodiscard]] std::size_t ContentRows() const
+	{
+		// Always compute from current rows_ to avoid stale values.
+		// Reserve 1 row for status line.
+		if (rows_ == 0)
+			return 1;
+		return std::max<std::size_t>(1, rows_ - 1);
+	}
+
+
 	// Mode and flags (mirroring legacy fields)
 	void SetMode(int m)
 	{

GUIFrontend.cc

@@ -203,28 +203,7 @@ GUIFrontend::Step(Editor &ed, bool &running)
 		input_.ProcessSDLEvent(e);
 	}
 
-	// Execute pending mapped inputs (drain queue)
-	for (;;) {
-		MappedInput mi;
-		if (!input_.Poll(mi))
-			break;
-		if (mi.hasCommand) {
-			// Track kill ring before and after to sync GUI clipboard when it changes
-			const std::string before = ed.KillRingHead();
-			Execute(ed, mi.id, mi.arg, mi.count);
-			const std::string after = ed.KillRingHead();
-			if (after != before && !after.empty()) {
-				// Update the system clipboard to mirror the kill ring head in GUI
-				SDL_SetClipboardText(after.c_str());
-			}
-		}
-	}
-
-	if (ed.QuitRequested()) {
-		running = false;
-	}
-
-	// Start a new ImGui frame
+	// Start a new ImGui frame BEFORE processing commands so dimensions are correct
 	ImGui_ImplOpenGL3_NewFrame();
 	ImGui_ImplSDL2_NewFrame(window_);
 	ImGui::NewFrame();
@@ -264,6 +243,27 @@ GUIFrontend::Step(Editor &ed, bool &running)
 		}
 	}
 
+	// Execute pending mapped inputs (drain queue) AFTER dimensions are updated
+	for (;;) {
+		MappedInput mi;
+		if (!input_.Poll(mi))
+			break;
+		if (mi.hasCommand) {
+			// Track kill ring before and after to sync GUI clipboard when it changes
+			const std::string before = ed.KillRingHead();
+			Execute(ed, mi.id, mi.arg, mi.count);
+			const std::string after = ed.KillRingHead();
+			if (after != before && !after.empty()) {
+				// Update the system clipboard to mirror the kill ring head in GUI
+				SDL_SetClipboardText(after.c_str());
+			}
+		}
+	}
+
+	if (ed.QuitRequested()) {
+		running = false;
+	}
+
 	// No runtime font UI; always use embedded font.
 
 	// Draw editor UI

GUIInputHandler.cc

@@ -285,15 +285,11 @@ GUIInputHandler::ProcessSDLEvent(const SDL_Event &e)
 	bool produced = false;
 	switch (e.type) {
 	case SDL_MOUSEWHEEL: {
-		// If ImGui wants to capture the mouse (e.g., hovering the File Picker list),
-		// don't translate wheel events into editor scrolling.
-		// This prevents background buffer scroll while using GUI widgets.
-		ImGuiIO &io = ImGui::GetIO();
-		if (io.WantCaptureMouse) {
-			return true; // consumed by GUI
-		}
-
-		// Map vertical wheel to line-wise cursor movement (MoveUp/MoveDown)
+		// Map vertical wheel to viewport scrolling (ScrollUp/ScrollDown)
+		// Note: We don't check WantCaptureMouse here because ImGui sets it to true
+		// whenever the mouse is over any ImGui window (including our editor content area).
+		// The NoScrollWithMouse flag on the child window prevents ImGui from handling
+		// scroll internally, so we can safely process wheel events ourselves.
 		int dy = e.wheel.y;
 #ifdef SDL_MOUSEWHEEL_FLIPPED
 		if (e.wheel.direction == SDL_MOUSEWHEEL_FLIPPED)
@@ -301,7 +297,7 @@ GUIInputHandler::ProcessSDLEvent(const SDL_Event &e)
 #endif
 		if (dy != 0) {
 			int repeat   = dy > 0 ? dy : -dy;
-			CommandId id = dy > 0 ? CommandId::MoveUp : CommandId::MoveDown;
+			CommandId id = dy > 0 ? CommandId::ScrollUp : CommandId::ScrollDown;
 			std::lock_guard<std::mutex> lk(mu_);
 			for (int i = 0; i < repeat; ++i) {
 				q_.push(MappedInput{true, id, std::string(), 0});
@@ -564,7 +560,12 @@ GUIInputHandler::ProcessSDLEvent(const SDL_Event &e)
 
 	if (produced && mi.hasCommand) {
 		// Attach universal-argument count if present, then clear the state
-		if (uarg_active_ && mi.id != CommandId::UArgStatus) {
+		if (uarg_active_ &&mi
+		
+		.
+		id != CommandId::UArgStatus
+		)
+		{
 			int count = 0;
 			if (!uarg_had_digits_ && !uarg_negative_) {
 				count = (uarg_value_ > 0) ? uarg_value_ : 4;

GUIRenderer.cc

@@ -67,54 +67,65 @@ GUIRenderer::Draw(Editor &ed)
 		ImGui::TextUnformatted("[no buffer]");
 	} else {
 		const auto &lines   = buf->Rows();
-		// Reserve space for status bar at bottom
-		ImGui::BeginChild("scroll", ImVec2(0, -ImGui::GetFrameHeightWithSpacing()), false,
-		                  ImGuiWindowFlags_HorizontalScrollbar | ImGuiWindowFlags_NoScrollWithMouse);
-		// Detect click-to-move inside this scroll region
-		ImVec2 list_origin  = ImGui::GetCursorScreenPos();
-		float scroll_y      = ImGui::GetScrollY();
-		float scroll_x      = ImGui::GetScrollX();
-		std::size_t rowoffs = 0; // we render from the first line; scrolling is handled by ImGui
 		std::size_t cy      = buf->Cury();
 		std::size_t cx      = buf->Curx();
 		const float line_h  = ImGui::GetTextLineHeight();
 		const float row_h   = ImGui::GetTextLineHeightWithSpacing();
 		const float space_w = ImGui::CalcTextSize(" ").x;
+
 		// Two-way sync between Buffer::Rowoffs and ImGui scroll position:
 		// - If command layer changed Buffer::Rowoffs since last frame, drive ImGui scroll from it.
 		// - Otherwise, propagate ImGui scroll to Buffer::Rowoffs so command layer has an up-to-date view.
-		// This prevents clicks/wheel from being immediately overridden by stale offsets.
-		bool forced_scroll = false;
-		{
 		static long prev_buf_rowoffs = -1; // previous frame's Buffer::Rowoffs
 		static long prev_buf_coloffs = -1; // previous frame's Buffer::Coloffs
-			static float prev_scroll_y   = -1.0f; // previous frame's ImGui scroll Y in pixels
-			static float prev_scroll_x   = -1.0f; // previous frame's ImGui scroll X in pixels
 
 		const long buf_rowoffs = static_cast<long>(buf->Rowoffs());
 		const long buf_coloffs = static_cast<long>(buf->Coloffs());
+
+		// Detect programmatic change (e.g., page_down command changed rowoffs)
+		// Use SetNextWindowScroll BEFORE BeginChild to set initial scroll position
+		if (prev_buf_rowoffs >= 0 && buf_rowoffs != prev_buf_rowoffs) {
+			float target_y = static_cast<float>(buf_rowoffs) * row_h;
+			ImGui::SetNextWindowScroll(ImVec2(-1.0f, target_y));
+		}
+		if (prev_buf_coloffs >= 0 && buf_coloffs != prev_buf_coloffs) {
+			float target_x = static_cast<float>(buf_coloffs) * space_w;
+			float target_y = static_cast<float>(buf_rowoffs) * row_h;
+			ImGui::SetNextWindowScroll(ImVec2(target_x, target_y));
+		}
+
+		// Reserve space for status bar at bottom
+		ImGui::BeginChild("scroll", ImVec2(0, -ImGui::GetFrameHeightWithSpacing()), false,
+		                  ImGuiWindowFlags_HorizontalScrollbar | ImGuiWindowFlags_NoScrollWithMouse);
+
+		// Get child window position and scroll for click handling
+		ImVec2 child_window_pos = ImGui::GetWindowPos();
+		float scroll_y          = ImGui::GetScrollY();
+		float scroll_x          = ImGui::GetScrollX();
+		std::size_t rowoffs     = 0; // we render from the first line; scrolling is handled by ImGui
+
+		// Synchronize buffer offsets from ImGui scroll if user scrolled manually
+		bool forced_scroll = false;
+		{
+			static float prev_scroll_y = -1.0f; // previous frame's ImGui scroll Y in pixels
+			static float prev_scroll_x = -1.0f; // previous frame's ImGui scroll X in pixels
+
 			const long scroll_top  = static_cast<long>(scroll_y / row_h);
 			const long scroll_left = static_cast<long>(scroll_x / space_w);
 
-			// Detect programmatic change (e.g., keyboard navigation ensured visibility)
+			// Check if rowoffs was programmatically changed this frame
 			if (prev_buf_rowoffs >= 0 && buf_rowoffs != prev_buf_rowoffs) {
-				ImGui::SetScrollY(static_cast<float>(buf_rowoffs) * row_h);
-				scroll_y      = ImGui::GetScrollY();
 				forced_scroll = true;
 			}
-			if (prev_buf_coloffs >= 0 && buf_coloffs != prev_buf_coloffs) {
-				ImGui::SetScrollX(static_cast<float>(buf_coloffs) * space_w);
-				scroll_x      = ImGui::GetScrollX();
-				forced_scroll = true;
-			}
-			// If user scrolled, update buffer offsets accordingly
-			if (prev_scroll_y >= 0.0f && scroll_y != prev_scroll_y) {
+
+			// If user scrolled (not programmatic), update buffer offsets accordingly
+			if (prev_scroll_y >= 0.0f && scroll_y != prev_scroll_y && !forced_scroll) {
 				if (Buffer *mbuf = const_cast<Buffer *>(buf)) {
 					mbuf->SetOffsets(static_cast<std::size_t>(std::max(0L, scroll_top)),
 					                 mbuf->Coloffs());
 				}
 			}
-			if (prev_scroll_x >= 0.0f && scroll_x != prev_scroll_x) {
+			if (prev_scroll_x >= 0.0f && scroll_x != prev_scroll_x && !forced_scroll) {
 				if (Buffer *mbuf = const_cast<Buffer *>(buf)) {
 					mbuf->SetOffsets(mbuf->Rowoffs(),
 					                 static_cast<std::size_t>(std::max(0L, scroll_left)));
@@ -122,11 +133,12 @@ GUIRenderer::Draw(Editor &ed)
 			}
 
 			// Update trackers for next frame
-			prev_buf_rowoffs = static_cast<long>(buf->Rowoffs());
-			prev_buf_coloffs = static_cast<long>(buf->Coloffs());
-			prev_scroll_y    = ImGui::GetScrollY();
-			prev_scroll_x    = ImGui::GetScrollX();
+			prev_scroll_y = scroll_y;
+			prev_scroll_x = scroll_x;
 		}
+		prev_buf_rowoffs = buf_rowoffs;
+		prev_buf_coloffs = buf_coloffs;
+
 		// Synchronize cursor and scrolling.
 		// Ensure the cursor is visible even on the first frame or when it didn't move,
 		// unless we already forced scrolling from Buffer::Rowoffs this frame.
@@ -165,24 +177,16 @@ GUIRenderer::Draw(Editor &ed)
 		// Handle mouse click before rendering to avoid dependent on drawn items
 		if (ImGui::IsWindowHovered() && ImGui::IsMouseClicked(ImGuiMouseButton_Left)) {
 			ImVec2 mp = ImGui::GetIO().MousePos;
-			// Compute viewport-relative row so (0) is top row of the visible area
-			float vy_f = (mp.y - list_origin.y - scroll_y) / row_h;
-			long vy    = static_cast<long>(vy_f);
-			if (vy < 0)
-				vy = 0;
+			// Compute content-relative position accounting for scroll
+			// mp.y - child_window_pos.y gives us pixels from top of child window
+			// Adding scroll_y gives us pixels from top of content (buffer row 0)
+			float content_y = (mp.y - child_window_pos.y) + scroll_y;
+			long by_l       = static_cast<long>(content_y / row_h);
+			if (by_l < 0)
+				by_l = 0;
 
-			// Clamp vy within visible content height to avoid huge jumps
-			ImVec2 cr_min = ImGui::GetWindowContentRegionMin();
-			ImVec2 cr_max = ImGui::GetWindowContentRegionMax();
-			float child_h = (cr_max.y - cr_min.y);
-			long vis_rows = static_cast<long>(child_h / row_h);
-			if (vis_rows < 1)
-				vis_rows = 1;
-			if (vy >= vis_rows)
-				vy = vis_rows - 1;
-
-			// Translate viewport row to buffer row using Buffer::Rowoffs
-			std::size_t by = buf->Rowoffs() + static_cast<std::size_t>(vy);
+			// Convert to buffer row
+			std::size_t by = static_cast<std::size_t>(by_l);
 			if (by >= lines.size()) {
 				if (!lines.empty())
 					by = lines.size() - 1;
@@ -190,58 +194,43 @@ GUIRenderer::Draw(Editor &ed)
 					by = 0;
 			}
 
-			// Compute desired pixel X inside the viewport content (subtract horizontal scroll)
-			float px = (mp.x - list_origin.x - scroll_x);
-			if (px < 0.0f)
-				px = 0.0f;
+			// Compute content-relative X position accounting for scroll
+			// mp.x - child_window_pos.x gives us pixels from left edge of child window
+			// Adding scroll_x gives us pixels from left edge of content (column 0)
+			float content_x = (mp.x - child_window_pos.x) + scroll_x;
+			if (content_x < 0.0f)
+				content_x = 0.0f;
 
 			// Empty buffer guard: if there are no lines yet, just move to 0:0
 			if (lines.empty()) {
 				Execute(ed, CommandId::MoveCursorTo, std::string("0:0"));
 			} else {
-				// Convert pixel X to a render-column target including horizontal col offset
-				// Use our own tab expansion of width 8 to match command layer logic.
+				// Convert pixel X to source column accounting for tabs
 				std::string line_clicked = static_cast<std::string>(lines[by]);
 				const std::size_t tabw   = 8;
-				// We iterate source columns computing absolute rendered column (rx_abs) from 0,
-				// then translate to viewport-space by subtracting Coloffs.
-				std::size_t coloffs = buf->Coloffs();
-				std::size_t rx_abs  = 0; // absolute rendered column
-				std::size_t i       = 0; // source column iterator
 
-				// Fast-forward i until rx_abs >= coloffs to align with leftmost visible column
-				if (!line_clicked.empty() && coloffs > 0) {
-					while (i < line_clicked.size() && rx_abs < coloffs) {
-						if (line_clicked[i] == '\t') {
-							rx_abs += (tabw - (rx_abs % tabw));
-						} else {
-							rx_abs += 1;
-						}
-						++i;
-					}
-				}
-
-				// Now search for closest source column to clicked px within/after viewport
-				std::size_t best_col = i; // default to first visible column
+				// Iterate through source columns, computing rendered position, to find closest match
+				std::size_t rx       = 0; // rendered column position
+				std::size_t best_col = 0;
 				float best_dist      = std::numeric_limits<float>::infinity();
-				while (true) {
-					// For i in [current..size], evaluate candidate including the implicit end position
-					std::size_t rx_view = (rx_abs >= coloffs) ? (rx_abs - coloffs) : 0;
-					float rx_px         = static_cast<float>(rx_view) * space_w;
-					float dist          = std::fabs(px - rx_px);
-					if (dist <= best_dist) {
+
+				for (std::size_t i = 0; i <= line_clicked.size(); ++i) {
+					// Check current position
+					float rx_px = static_cast<float>(rx) * space_w;
+					float dist  = std::fabs(content_x - rx_px);
+					if (dist < best_dist) {
 						best_dist = dist;
 						best_col  = i;
 					}
-					if (i == line_clicked.size())
-						break;
-					// advance to next source column
+
+					// Advance to next position if not at end
+					if (i < line_clicked.size()) {
 						if (line_clicked[i] == '\t') {
-						rx_abs += (tabw - (rx_abs % tabw));
+							rx += (tabw - (rx % tabw));
 						} else {
-						rx_abs += 1;
+							rx += 1;
+						}
 					}
-					++i;
 				}
 
 				// Dispatch absolute buffer coordinates (row:col)
@@ -374,7 +363,8 @@ GUIRenderer::Draw(Editor &ed)
 						p, col, expanded.c_str() + vx0, expanded.c_str() + vx1);
 				}
 				// We drew text via draw list (no layout advance). Manually advance the cursor to the next line.
-				ImGui::SetCursorScreenPos(ImVec2(line_pos.x, line_pos.y + line_h));
+				// Use row_h (with spacing) to match click calculation and ensure consistent line positions.
+				ImGui::SetCursorScreenPos(ImVec2(line_pos.x, line_pos.y + row_h));
 			} else {
 				// No syntax: draw as one run
 				ImGui::TextUnformatted(expanded.c_str());

TerminalInputHandler.cc

@@ -35,16 +35,16 @@ map_key_to_command(const int ch,
 	case KEY_MOUSE: {
 		MEVENT ev{};
 		if (getmouse(&ev) == OK) {
-			// Mouse wheel → map to MoveUp/MoveDown one line per wheel notch
+			// Mouse wheel → scroll viewport without moving cursor
 #ifdef BUTTON4_PRESSED
 			if (ev.bstate & (BUTTON4_PRESSED | BUTTON4_RELEASED | BUTTON4_CLICKED)) {
-				out = {true, CommandId::MoveUp, "", 0};
+				out = {true, CommandId::ScrollUp, "", 0};
 				return true;
 			}
 #endif
 #ifdef BUTTON5_PRESSED
 			if (ev.bstate & (BUTTON5_PRESSED | BUTTON5_RELEASED | BUTTON5_CLICKED)) {
-				out = {true, CommandId::MoveDown, "", 0};
+				out = {true, CommandId::ScrollDown, "", 0};
 				return true;
 			}
 #endif

TerminalRenderer.cc

@@ -34,6 +34,8 @@ TerminalRenderer::Draw(Editor &ed)
 
 	const Buffer *buf = ed.CurrentBuffer();
 	int content_rows  = rows - 1; // last line is status
+	if (content_rows < 1)
+		content_rows = 1;
 
 	int saved_cur_y = -1, saved_cur_x = -1; // logical cursor position within content area
 	if (buf) {