Basic renderers and input handlers

src/cpp/renderer.cpp

@@ -0,0 +1,260 @@
+// includes
+#include "../../libs/libgrapheme/grapheme.h"
+#include "../../libs/unicode_width/unicode_width.h"
+#include "../headers/header.hpp"
+
+struct termios orig_termios;
+
+int rows, cols;
+bool show_cursor = false;
+std::vector<ScreenCell> screen;
+std::vector<ScreenCell> old_screen;
+std::mutex screen_mutex;
+
+int real_width(std::string str) {
+  if (!str.size())
+    return 0;
+  const char *p = str.c_str();
+  if (str[0] == '\t')
+    return 4;
+  unicode_width_state_t state;
+  unicode_width_init(&state);
+  int width = 0;
+  for (size_t j = 0; j < str.size(); j++) {
+    unsigned char c = str[j];
+    if (c < 128) {
+      int char_width = unicode_width_process(&state, c);
+      if (char_width > 0)
+        width += char_width;
+    } else {
+      uint_least32_t cp;
+      size_t bytes = grapheme_decode_utf8(p + j, str.size() - j, &cp);
+      if (bytes > 1) {
+        int char_width = unicode_width_process(&state, cp);
+        if (char_width > 0)
+          width += char_width;
+        j += bytes - 1;
+      }
+    }
+  }
+  return width;
+}
+
+void get_terminal_size() {
+  struct winsize w;
+  ioctl(0, TIOCGWINSZ, &w);
+  rows = w.ws_row;
+  cols = w.ws_col;
+}
+
+void die(const char *s) {
+  perror(s);
+  disable_raw_mode();
+  exit(EXIT_FAILURE);
+}
+
+void enable_raw_mode() {
+  if (tcgetattr(STDIN_FILENO, &orig_termios) == -1)
+    die("tcgetattr");
+  atexit(disable_raw_mode);
+
+  struct termios raw = orig_termios;
+  raw.c_iflag &= ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON);
+  raw.c_oflag &= ~(OPOST);
+  raw.c_cflag |= (CS8);
+  raw.c_lflag &= ~(ECHO | ICANON | IEXTEN | ISIG);
+  raw.c_cc[VMIN] = 0;
+  raw.c_cc[VTIME] = 0;
+
+  if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == -1)
+    die("tcsetattr");
+
+  std::string os = "\x1b[?1049h\x1b[2 q\x1b[?1002h\x1b[?25l";
+  write(STDOUT_FILENO, os.c_str(), os.size());
+}
+
+void disable_raw_mode() {
+  std::string os = "\x1b[?1049l\x1b[?25h";
+  write(STDOUT_FILENO, os.c_str(), os.size());
+  if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &orig_termios) == -1) {
+    perror("tcsetattr");
+    exit(EXIT_FAILURE);
+  }
+}
+
+void start_screen() {
+  enable_raw_mode();
+  get_terminal_size();
+  screen.assign(rows * cols, {});     // allocate & zero-init
+  old_screen.assign(rows * cols, {}); // allocate & zero-init
+}
+
+void end_screen() { disable_raw_mode(); }
+
+void update(int row, int col, const char *utf8, uint32_t fg, uint32_t bg,
+            uint8_t flags) {
+  if (row < 0 || row >= rows || col < 0 || col >= cols)
+    return;
+
+  int idx = row * cols + col;
+  std::lock_guard<std::mutex> lock(screen_mutex);
+
+  screen[idx].utf8 = utf8 ? utf8 : ""; // nullptr => empty string
+  screen[idx].fg = fg;
+  screen[idx].bg = bg;
+  screen[idx].flags = flags;
+}
+
+coords get_size() { return {rows, cols}; }
+
+void render() {
+  static bool first_render = true;
+  uint32_t current_fg = 0;
+  uint32_t current_bg = 0;
+  bool current_italic = false;
+  bool current_bold = false;
+  bool current_underline = false;
+
+  std::lock_guard<std::mutex> lock(screen_mutex);
+
+  std::string out;
+  // reserve a conservative amount to avoid repeated reallocs
+  out.reserve(static_cast<size_t>(rows) * static_cast<size_t>(cols) * 4 + 256);
+
+  // save cursor + hide
+  out += "\x1b[s\x1b[?25l";
+
+  if (first_render) {
+    out += "\x1b[2J\x1b[H";
+    first_render = false;
+  }
+
+  for (int row = 0; row < rows; ++row) {
+    int first_change_col = -1;
+    int last_change_col = -1;
+
+    // detect change span in this row
+    for (int col = 0; col < cols; ++col) {
+      int idx = row * cols + col;
+      ScreenCell &old_cell = old_screen[idx];
+      ScreenCell &new_cell = screen[idx];
+
+      bool old_empty = old_cell.utf8.empty();
+      bool new_empty = new_cell.utf8.empty();
+
+      bool content_changed =
+          (old_empty && !new_empty) || (!old_empty && new_empty) ||
+          (!old_empty && !new_empty && old_cell.utf8 != new_cell.utf8);
+
+      bool style_changed =
+          (old_cell.fg != new_cell.fg) || (old_cell.bg != new_cell.bg) ||
+          ((old_cell.flags & CF_ITALIC) != (new_cell.flags & CF_ITALIC)) ||
+          ((old_cell.flags & CF_BOLD) != (new_cell.flags & CF_BOLD)) ||
+          ((old_cell.flags & CF_UNDERLINE) != (new_cell.flags & CF_UNDERLINE));
+
+      if (content_changed || style_changed) {
+        if (first_change_col == -1)
+          first_change_col = col;
+        last_change_col = col;
+      }
+    }
+
+    if (first_change_col == -1)
+      continue;
+
+    // move cursor once to the start of change region
+    char buf[32];
+    int n = snprintf(buf, sizeof(buf), "\x1b[%d;%dH", row + 1,
+                     first_change_col + 1);
+    out.append(buf, n);
+
+    // render changed region
+    for (int col = first_change_col; col <= last_change_col; ++col) {
+      int idx = row * cols + col;
+      ScreenCell &old_cell = old_screen[idx];
+      ScreenCell &new_cell = screen[idx];
+
+      // foreground change
+      if (current_fg != new_cell.fg) {
+        if (new_cell.fg) {
+          char fb[64];
+          int m = snprintf(
+              fb, sizeof(fb), "\x1b[38;2;%d;%d;%dm", (new_cell.fg >> 16) & 0xFF,
+              (new_cell.fg >> 8) & 0xFF, (new_cell.fg >> 0) & 0xFF);
+          out.append(fb, m);
+        } else {
+          out += "\x1b[39m";
+        }
+        current_fg = new_cell.fg;
+      }
+
+      // background change
+      if (current_bg != new_cell.bg) {
+        if (new_cell.bg) {
+          char bb[64];
+          int m = snprintf(
+              bb, sizeof(bb), "\x1b[48;2;%d;%d;%dm", (new_cell.bg >> 16) & 0xFF,
+              (new_cell.bg >> 8) & 0xFF, (new_cell.bg >> 0) & 0xFF);
+          out.append(bb, m);
+        } else {
+          out += "\x1b[49m";
+        }
+        current_bg = new_cell.bg;
+      }
+
+      // italic
+      bool italic = (new_cell.flags & CF_ITALIC) != 0;
+      if (italic != current_italic) {
+        out += italic ? "\x1b[3m" : "\x1b[23m";
+        current_italic = italic;
+      }
+
+      // bold
+      bool bold = (new_cell.flags & CF_BOLD) != 0;
+      if (bold != current_bold) {
+        out += bold ? "\x1b[1m" : "\x1b[22m";
+        current_bold = bold;
+      }
+
+      // underline
+      bool underline = (new_cell.flags & CF_UNDERLINE) != 0;
+      if (underline != current_underline) {
+        out += underline ? "\x1b[4m" : "\x1b[24m";
+        current_underline = underline;
+      }
+
+      // content
+      if (!new_cell.utf8.empty()) {
+        if (new_cell.utf8[0] == '\t')
+          out.append("    ");
+        else
+          out.append(new_cell.utf8);
+      } else {
+        out.append(1, ' ');
+      }
+
+      // copy new -> old (std::string assignment, no strdup/free)
+      old_cell.utf8 = new_cell.utf8;
+      old_cell.fg = new_cell.fg;
+      old_cell.bg = new_cell.bg;
+      old_cell.flags = new_cell.flags;
+    }
+  }
+
+  // final reset + restore cursor + show cursor
+  out += "\x1b[0m";
+  out += "\x1b[u";
+  if (show_cursor)
+    out += "\x1b[?25h";
+
+  // single syscall to write the whole frame
+  ssize_t written = write(STDOUT_FILENO, out.data(), out.size());
+  (void)written; // you may check for errors in debug builds
+}
+
+void set_cursor(int row, int col, bool show_cursor_param) {
+  char buf[32];
+  int n = snprintf(buf, sizeof(buf), "\x1b[%d;%dH", row + 1, col + 1);
+  show_cursor = show_cursor_param;
+  write(STDOUT_FILENO, buf, n);
+}