Epic caret tweaks

Signed-off-by: Slendi <slendi@socopon.com>

src/App.cpp

@@ -189,23 +189,57 @@ auto App::init_wayland() -> void
 				bool ctrl = app->m_kbd.mod_active("Control");
 				bool alt = app->m_kbd.mod_active("Mod1");
 				bool meta = app->m_kbd.mod_active("Mod4");
-				if (!(ctrl || alt || meta)) {
-					if (sym == XKB_KEY_Left) {
-						app->m_kbd.typing.push_back(1);
-					} else if (sym == XKB_KEY_Down) {
-						app->m_kbd.typing.push_back(2);
-					} else if (sym == XKB_KEY_Up) {
-						app->m_kbd.typing.push_back(3);
-					} else if (sym == XKB_KEY_Right) {
-						app->m_kbd.typing.push_back(4);
-					} else {
-						u32 cp = xkb_keysym_to_utf32(sym);
-						if (cp >= 0x20) {
-							char buf[8];
-							int n = xkb_keysym_to_utf8(sym, buf, sizeof(buf));
-							if (n > 0)
-								app->m_kbd.typing.push_utf8(buf);
-						}
+
+				bool handled = false;
+				switch (sym) {
+				case XKB_KEY_Left:
+					app->m_kbd.typing.push_back(1);
+					handled = true;
+					break;
+				case XKB_KEY_Down:
+					app->m_kbd.typing.push_back(2);
+					handled = true;
+					break;
+				case XKB_KEY_Up:
+					app->m_kbd.typing.push_back(3);
+					handled = true;
+					break;
+				case XKB_KEY_Right:
+					app->m_kbd.typing.push_back(4);
+					handled = true;
+					break;
+				case XKB_KEY_BackSpace:
+					app->m_kbd.typing.push_back(8);
+					handled = true;
+					break;
+				case XKB_KEY_Delete:
+				case XKB_KEY_KP_Delete:
+					app->m_kbd.typing.push_back(0x7F);
+					handled = true;
+					break;
+				case XKB_KEY_Return:
+				case XKB_KEY_KP_Enter:
+					app->m_kbd.typing.push_back('\n');
+					handled = true;
+					break;
+				case XKB_KEY_w:
+				case XKB_KEY_W:
+					if (ctrl) {
+						app->m_kbd.typing.push_back(8);
+						handled = true;
+					}
+					break;
+				default:
+					break;
+				}
+
+				if (!handled && !(ctrl || alt || meta)) {
+					u32 cp = xkb_keysym_to_utf32(sym);
+					if (cp >= 0x20) {
+						char buf[8];
+						int n = xkb_keysym_to_utf8(sym, buf, sizeof(buf));
+						if (n > 0)
+							app->m_kbd.typing.push_utf8(buf);
 					}
 				}
 			} else {
@@ -346,6 +380,7 @@ auto App::init_egl() -> void
 	auto const font_handle = m_tr->load_font(*font, std::span(fallback_paths));
 	assert(font_handle && "Could not load font");
 	m_font = *font_handle;
+	m_gui->set_font(m_font);
 }
 
 auto App::init_signal() -> void

src/ImGui.cpp

@@ -1,9 +1,125 @@
 #include "ImGui.hpp"
 
+#include <algorithm>
 #include <cassert>
+#include <cctype>
+#include <cmath>
+#include <format>
+#include <string>
+#include <string_view>
+#include <vector>
 
 #include <raylib.h>
 
+namespace {
+
+struct CodepointSpan {
+	u32 codepoint {};
+	std::size_t start {};
+	std::size_t end {};
+};
+
+auto decode_utf8(std::string_view text) -> std::vector<CodepointSpan>
+{
+	std::vector<CodepointSpan> spans;
+	std::size_t i = 0;
+	spans.reserve(text.size());
+
+	while (i < text.size()) {
+		u8 const byte = static_cast<u8>(text[i]);
+		std::size_t const start = i;
+		std::size_t length = 1;
+		u32 cp = 0xFFFD;
+
+		if (byte < 0x80) {
+			cp = byte;
+		} else if ((byte & 0xE0) == 0xC0) {
+			if (i + 1 < text.size()) {
+				u8 const b1 = static_cast<u8>(text[i + 1]);
+				if ((b1 & 0xC0) == 0x80) {
+					u32 const t = ((static_cast<u32>(byte) & 0x1F) << 6)
+					    | (static_cast<u32>(b1) & 0x3F);
+					if (t >= 0x80) {
+						cp = t;
+						length = 2;
+					}
+				}
+			}
+		} else if ((byte & 0xF0) == 0xE0) {
+			if (i + 2 < text.size()) {
+				u8 const b1 = static_cast<u8>(text[i + 1]);
+				u8 const b2 = static_cast<u8>(text[i + 2]);
+				if ((b1 & 0xC0) == 0x80 && (b2 & 0xC0) == 0x80) {
+					u32 const t = ((static_cast<u32>(byte) & 0x0F) << 12)
+					    | ((static_cast<u32>(b1) & 0x3F) << 6)
+					    | (static_cast<u32>(b2) & 0x3F);
+					if (t >= 0x800 && (t < 0xD800 || t > 0xDFFF)) {
+						cp = t;
+						length = 3;
+					}
+				}
+			}
+		} else if ((byte & 0xF8) == 0xF0) {
+			if (i + 3 < text.size()) {
+				u8 const b1 = static_cast<u8>(text[i + 1]);
+				u8 const b2 = static_cast<u8>(text[i + 2]);
+				u8 const b3 = static_cast<u8>(text[i + 3]);
+				if ((b1 & 0xC0) == 0x80 && (b2 & 0xC0) == 0x80
+				    && (b3 & 0xC0) == 0x80) {
+					u32 const t = ((static_cast<u32>(byte) & 0x07) << 18)
+					    | ((static_cast<u32>(b1) & 0x3F) << 12)
+					    | ((static_cast<u32>(b2) & 0x3F) << 6)
+					    | (static_cast<u32>(b3) & 0x3F);
+					if (t >= 0x10000 && t <= 0x10FFFF) {
+						cp = t;
+						length = 4;
+					}
+				}
+			}
+		}
+
+		spans.push_back(CodepointSpan { cp, start, start + length });
+		i += length;
+	}
+
+	return spans;
+}
+
+auto encode_utf8(u32 cp) -> std::string
+{
+	char buf[5] = { 0, 0, 0, 0, 0 };
+	int len = 0;
+	if (cp <= 0x7F) {
+		buf[len++] = static_cast<char>(cp);
+	} else if (cp <= 0x7FF) {
+		buf[len++] = static_cast<char>(0xC0 | (cp >> 6));
+		buf[len++] = static_cast<char>(0x80 | (cp & 0x3F));
+	} else if (cp <= 0xFFFF) {
+		if (cp >= 0xD800 && cp <= 0xDFFF)
+			return {};
+		buf[len++] = static_cast<char>(0xE0 | (cp >> 12));
+		buf[len++] = static_cast<char>(0x80 | ((cp >> 6) & 0x3F));
+		buf[len++] = static_cast<char>(0x80 | (cp & 0x3F));
+	} else if (cp <= 0x10FFFF) {
+		buf[len++] = static_cast<char>(0xF0 | (cp >> 18));
+		buf[len++] = static_cast<char>(0x80 | ((cp >> 12) & 0x3F));
+		buf[len++] = static_cast<char>(0x80 | ((cp >> 6) & 0x3F));
+		buf[len++] = static_cast<char>(0x80 | (cp & 0x3F));
+	} else {
+		return {};
+	}
+	return std::string(buf, len);
+}
+
+constexpr float HORIZONTAL_PADDING = 6.0f;
+constexpr float VERTICAL_PADDING = 4.0f;
+constexpr float CARET_WIDTH = 2.0f;
+constexpr float CARET_INSET = 1.0f;
+constexpr double CARET_BLINK_INTERVAL = 0.5;
+constexpr float CARET_DESCENT_FRACTION = 0.25f;
+
+} // namespace
+
 ImGui::ImGui(std::shared_ptr<TextRenderer> text_renderer)
     : m_text_renderer(text_renderer)
 {
@@ -18,20 +134,25 @@ void ImGui::begin(u32 const rune, bool ctrl, bool shift)
 
 void ImGui::end() { }
 
+void ImGui::set_font(FontHandle font) { m_font = font; }
+
 auto ImGui::text_input(std::size_t id, std::pmr::string &str, Rectangle rec,
     TextInputOptions options) -> std::bitset<2>
 {
 	assert(id != 0);
+	assert(
+	    m_font.has_value() && "ImGui font must be set before using text input");
 
 	bool submitted { false };
 	bool changed { false };
 
-	if (!m_ti_states.contains(id)) {
-		m_ti_states[id] = {};
-	}
+	auto &state = m_ti_states[id];
 
 	assert(!options.multiline && "Multiline not yet implemented.");
 
+	if (m_focused_id == 0)
+		m_focused_id = id;
+
 	if (options.font_size > rec.height) {
 		TraceLog(LOG_WARNING,
 		    std::format("Text size for text input {} is bigger than height ({} "
@@ -40,8 +161,300 @@ auto ImGui::text_input(std::size_t id, std::pmr::string &str, Rectangle rec,
 		        .c_str());
 	}
 
+	std::string_view str_view(str.data(), str.size());
+	auto spans = decode_utf8(str_view);
+
+	auto is_space = [](u32 cp) -> bool {
+		if (cp == '\n' || cp == '\r' || cp == '\t' || cp == '\v' || cp == '\f')
+			return true;
+		if (cp <= 0x7F)
+			return std::isspace(static_cast<unsigned char>(cp)) != 0;
+		return false;
+	};
+
+	auto clamp_cursor = [&]() -> std::size_t {
+		int const max_idx = static_cast<int>(spans.size());
+		state.current_rune_idx = std::clamp(state.current_rune_idx, 0, max_idx);
+		if (state.current_rune_idx == max_idx)
+			return str.size();
+		return spans[state.current_rune_idx].start;
+	};
+
+	std::size_t caret_byte = clamp_cursor();
+
+	auto refresh_spans = [&]() {
+		str_view = std::string_view(str.data(), str.size());
+		spans = decode_utf8(str_view);
+		caret_byte = clamp_cursor();
+	};
+
+	auto erase_range = [&](std::size_t byte_begin, std::size_t byte_end) {
+		if (byte_end > byte_begin && byte_begin < str.size()) {
+			str.erase(byte_begin, byte_end - byte_begin);
+			changed = true;
+		}
+	};
+
+	bool caret_activity = false;
+
+	if (m_focused_id == id && m_rune != 0) {
+		bool request_refresh = false;
+		auto handle_backspace = [&]() {
+			if (state.current_rune_idx <= 0
+			    || state.current_rune_idx > static_cast<int>(spans.size()))
+				return;
+
+			if (m_ctrl) {
+				int idx = state.current_rune_idx;
+				int scan = idx - 1;
+				while (scan >= 0
+				    && is_space(
+				        spans[static_cast<std::size_t>(scan)].codepoint))
+					scan--;
+				while (scan >= 0
+				    && !is_space(
+				        spans[static_cast<std::size_t>(scan)].codepoint))
+					scan--;
+				int start_idx = std::max(scan + 1, 0);
+				std::size_t byte_begin
+				    = spans[static_cast<std::size_t>(start_idx)].start;
+				std::size_t byte_end = (idx >= static_cast<int>(spans.size()))
+				    ? str.size()
+				    : spans[static_cast<std::size_t>(idx)].start;
+				erase_range(byte_begin, byte_end);
+				state.current_rune_idx = start_idx;
+			} else {
+				auto const &prev = spans[static_cast<std::size_t>(
+				    state.current_rune_idx - 1)];
+				erase_range(prev.start, prev.end);
+				state.current_rune_idx--;
+			}
+			request_refresh = true;
+		};
+
+		auto handle_delete = [&]() {
+			if (state.current_rune_idx < 0
+			    || state.current_rune_idx >= static_cast<int>(spans.size())) {
+				if (!m_ctrl)
+					return;
+			}
+
+			int idx = state.current_rune_idx;
+			if (m_ctrl) {
+				int scan = idx;
+				while (scan < static_cast<int>(spans.size())
+				    && is_space(
+				        spans[static_cast<std::size_t>(scan)].codepoint))
+					scan++;
+				while (scan < static_cast<int>(spans.size())
+				    && !is_space(
+				        spans[static_cast<std::size_t>(scan)].codepoint))
+					scan++;
+				std::size_t byte_begin = (idx < static_cast<int>(spans.size()))
+				    ? spans[static_cast<std::size_t>(idx)].start
+				    : str.size();
+				std::size_t byte_end = (scan < static_cast<int>(spans.size()))
+				    ? spans[static_cast<std::size_t>(scan)].start
+				    : str.size();
+				erase_range(byte_begin, byte_end);
+			} else if (idx < static_cast<int>(spans.size())) {
+				auto const &curr = spans[static_cast<std::size_t>(idx)];
+				erase_range(curr.start, curr.end);
+			}
+			request_refresh = true;
+		};
+
+		switch (m_rune) {
+		case 1: // Left (H)
+			if (state.current_rune_idx > 0) {
+				state.current_rune_idx--;
+				if (m_ctrl) {
+					while (state.current_rune_idx > 0
+					    && is_space(spans[static_cast<std::size_t>(
+					                          state.current_rune_idx)]
+					            .codepoint))
+						state.current_rune_idx--;
+					while (state.current_rune_idx > 0
+					    && !is_space(spans[static_cast<std::size_t>(
+					                           state.current_rune_idx)]
+					            .codepoint))
+						state.current_rune_idx--;
+				}
+				caret_byte = clamp_cursor();
+			}
+			break;
+		case 4: // Right (L)
+			if (state.current_rune_idx < static_cast<int>(spans.size())) {
+				state.current_rune_idx++;
+				if (m_ctrl) {
+					while (
+					    state.current_rune_idx < static_cast<int>(spans.size())
+					    && is_space(spans[static_cast<std::size_t>(
+					                          state.current_rune_idx - 1)]
+					            .codepoint))
+						state.current_rune_idx++;
+					while (
+					    state.current_rune_idx < static_cast<int>(spans.size())
+					    && !is_space(spans[static_cast<std::size_t>(
+					                           state.current_rune_idx - 1)]
+					            .codepoint))
+						state.current_rune_idx++;
+				}
+				caret_byte = clamp_cursor();
+			}
+			break;
+		case 3: // Up (K)
+			state.current_rune_idx = 0;
+			caret_byte = clamp_cursor();
+			break;
+		case 2: // Down (J)
+			state.current_rune_idx = static_cast<int>(spans.size());
+			caret_byte = clamp_cursor();
+			break;
+		case 8: // Backspace
+			handle_backspace();
+			break;
+		case 0x7F: // Delete
+			handle_delete();
+			break;
+		case '\r':
+		case '\n':
+			if (options.multiline) {
+				auto encoded = encode_utf8('\n');
+				if (!encoded.empty()) {
+					str.insert(caret_byte, encoded);
+					state.current_rune_idx++;
+					changed = true;
+					request_refresh = true;
+				}
+			} else {
+				submitted = true;
+			}
+			break;
+		default:
+			if (m_rune >= 0x20) {
+				auto encoded = encode_utf8(m_rune);
+				if (!encoded.empty()) {
+					str.insert(caret_byte, encoded);
+					state.current_rune_idx++;
+					changed = true;
+					request_refresh = true;
+				}
+			}
+			break;
+		}
+
+		if (request_refresh) {
+			refresh_spans();
+		} else {
+			caret_byte = clamp_cursor();
+		}
+		caret_activity = true;
+	}
+
+	double const dt = static_cast<double>(GetFrameTime());
+	if (m_focused_id == id) {
+		if (caret_activity) {
+			state.caret_timer = 0.0;
+			state.caret_visible = true;
+		} else {
+			if (state.caret_timer == 0.0)
+				state.caret_visible = true;
+			state.caret_timer += dt;
+			if (state.caret_timer >= CARET_BLINK_INTERVAL) {
+				int toggles = static_cast<int>(state.caret_timer / CARET_BLINK_INTERVAL);
+				state.caret_timer
+				    = std::fmod(state.caret_timer, CARET_BLINK_INTERVAL);
+				if (toggles % 2 == 1)
+					state.caret_visible = !state.caret_visible;
+			}
+		}
+	} else {
+		state.caret_visible = false;
+		state.caret_timer = 0.0;
+	}
+
+	Vector2 prefix_metrics { 0.0f, 0.0f };
+	Vector2 full_metrics { 0.0f, 0.0f };
+	if (m_font.has_value() && m_text_renderer) {
+		std::string_view const prefix_view(str.data(), caret_byte);
+		prefix_metrics = m_text_renderer->measure_text(
+		    *m_font, prefix_view, static_cast<int>(options.font_size));
+		full_metrics = m_text_renderer->measure_text(
+		    *m_font, str_view, static_cast<int>(options.font_size));
+	}
+
+	state.cursor_position.x = prefix_metrics.x;
+
+	float const available_width
+	    = std::max(0.0f, rec.width - 2.0f * HORIZONTAL_PADDING);
+	if (full_metrics.x <= available_width) {
+		state.scroll_offset.x = 0.0f;
+	} else {
+		float &scroll = state.scroll_offset.x;
+		float caret_local = state.cursor_position.x - scroll;
+		if (caret_local > available_width) {
+			scroll = state.cursor_position.x - available_width;
+		} else if (caret_local < 0.0f) {
+			scroll = state.cursor_position.x;
+		}
+		scroll = std::clamp(
+		    scroll, 0.0f, std::max(0.0f, full_metrics.x - available_width));
+	}
+	state.scroll_offset.y = 0.0f;
+
+	Color const bg_col { 16, 16, 16, 100 };
+	Color const border_col { 220, 220, 220, 180 };
+	DrawRectangleRec(rec, bg_col);
+	DrawRectangleLinesEx(rec, 1.0f, border_col);
+
+	float const text_top = rec.y + VERTICAL_PADDING;
+	float const baseline_y = text_top + options.font_size;
+	float const max_caret_height
+	    = std::max(0.0f, rec.height - 2.0f * VERTICAL_PADDING);
+	float caret_height = options.font_size * (1.0f + CARET_DESCENT_FRACTION);
+	caret_height = std::min(caret_height,
+	    max_caret_height > 0.0f ? max_caret_height : caret_height);
+	if (caret_height <= 0.0f)
+		caret_height = options.font_size;
+	float caret_top = baseline_y - options.font_size;
+	float const min_top = rec.y + VERTICAL_PADDING;
+	float const max_top = rec.y + rec.height - VERTICAL_PADDING - caret_height;
+	caret_top = std::clamp(caret_top, min_top, max_top);
+	float caret_bottom = caret_top + caret_height;
+	float const desired_bottom = baseline_y + options.font_size * CARET_DESCENT_FRACTION;
+	if (caret_bottom < desired_bottom) {
+		float const adjust = desired_bottom - caret_bottom;
+		caret_top = std::min(caret_top + adjust, max_top);
+		caret_bottom = caret_top + caret_height;
+	}
+	state.cursor_position.y = caret_top;
+
 	BeginScissorMode(rec.x, rec.y, rec.width, rec.height);
 	{
+		if (m_font.has_value() && m_text_renderer) {
+			Vector2 const text_pos {
+				rec.x + HORIZONTAL_PADDING - state.scroll_offset.x,
+				baseline_y,
+			};
+			Color const text_color { 255, 255, 255, 255 };
+			m_text_renderer->draw_text(*m_font, str_view, text_pos,
+			    static_cast<int>(options.font_size), text_color);
+
+			if (m_focused_id == id && state.caret_visible) {
+				float const caret_x = std::round(rec.x + HORIZONTAL_PADDING
+				    + state.cursor_position.x - state.scroll_offset.x
+				    + CARET_INSET);
+				Rectangle caret_rect {
+					caret_x,
+					caret_top,
+					CARET_WIDTH,
+					caret_height,
+				};
+				Color const caret_color { 255, 255, 255, 200 };
+				DrawRectangleRec(caret_rect, caret_color);
+			}
+		}
 	}
 	EndScissorMode();
 

src/ImGui.hpp

@@ -2,12 +2,13 @@
 
 #include <bitset>
 #include <memory>
+#include <optional>
 
 #include <raylib.h>
 
 #include "TextRenderer.hpp"
 
-constexpr float DEFAULT_FONT_SIZE { 16 };
+constexpr float DEFAULT_FONT_SIZE { 24 };
 
 struct TextInputOptions {
 	bool multiline { false };
@@ -30,6 +31,8 @@ struct ImGui {
 	auto text_input(std::size_t id, std::pmr::string &str, Rectangle rec,
 	    TextInputOptions options = {}) -> std::bitset<2>;
 
+	void set_font(FontHandle font);
+
 	[[nodiscard]] inline auto id(std::string_view const str) -> std::size_t
 	{
 		std::hash<std::string_view> hasher;
@@ -41,6 +44,8 @@ private:
 		int current_rune_idx { 0 };
 		Vector2 scroll_offset;   // y not used if multiline == false
 		Vector2 cursor_position; // y not used if multiline == false
+		bool caret_visible { true };
+		double caret_timer { 0.0 };
 	};
 
 	std::unordered_map<std::size_t, TextInputState> m_ti_states;
@@ -49,6 +54,7 @@ private:
 	bool m_ctrl {};
 	bool m_shift {};
 
+	std::optional<FontHandle> m_font {};
 	std::shared_ptr<TextRenderer> m_text_renderer {};
 };
 

src/Tick.cpp

@@ -29,7 +29,6 @@ auto App::tick() -> void
 
 	ClearBackground(theme().window.background);
 
-	DrawFPS(10, 10);
 	{
 		assert(m_gui);
 		u32 rune { 0 };