Attempt to fix scrolling in vim

Atleast now it can "emulate" scrolling

cowterm.c

@@ -1,3 +1,4 @@
+#include <X11/X.h>
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
 #include <X11/keysym.h>
@@ -40,6 +41,8 @@ static Pixmap buffer_pixmap = None;
 static int master_fd = -1;
 static int needs_refresh = 0;
 static int window_focused = 0;
+static int scroll_top = 0;    // 0 means entire terminal
+static int scroll_bottom = 0; // 0 means entire terminal
 
 // Cursor stuff
 static int cursor_visible = 1;
@@ -435,6 +438,233 @@ static void scroll_up(void) {
   needs_refresh = 1;
 }
 
+static void scroll_region_up(int amount) {
+  char **temp_buffer = NULL;
+  unsigned long **temp_color_buffer = NULL;
+  int **temp_attr_buffer = NULL;
+  unsigned long **temp_bg_color_buffer = NULL;
+
+  temp_buffer = malloc(term_rows * sizeof(char *));
+  temp_color_buffer = malloc(term_rows * sizeof(unsigned long *));
+  temp_attr_buffer = malloc(term_rows * sizeof(int *));
+  temp_bg_color_buffer = malloc(term_rows * sizeof(unsigned long *));
+
+  if (!temp_buffer || !temp_color_buffer || !temp_attr_buffer ||
+      !temp_bg_color_buffer) {
+    fprintf(stderr, "Failed to allocate memory for temp buffers\n");
+    return;
+  }
+
+  for (int i = 0; i < term_rows; i++) {
+    temp_buffer[i] = malloc(term_cols * sizeof(char));
+    temp_color_buffer[i] = malloc(term_cols * sizeof(unsigned long));
+    temp_attr_buffer[i] = malloc(term_cols * sizeof(int));
+    temp_bg_color_buffer[i] = malloc(term_cols * sizeof(unsigned long));
+    if (!temp_buffer[i] || !temp_color_buffer[i] || !temp_attr_buffer[i] ||
+        !temp_bg_color_buffer[i]) {
+      fprintf(stderr, "Failed to allocate memory for temp buffer row\n");
+      free(temp_buffer);
+      free(temp_color_buffer);
+      free(temp_attr_buffer);
+      free(temp_bg_color_buffer);
+      return;
+    }
+  }
+
+  if (scroll_top == 0 && scroll_bottom == 0) {
+    for (int i = 0; i < term_rows; i++) {
+      memcpy(temp_buffer[i], terminal_buffer[i], term_cols * sizeof(char));
+      memcpy(temp_color_buffer[i], color_buffer[i],
+             term_cols * sizeof(unsigned long));
+      memcpy(temp_attr_buffer[i], attr_buffer[i], term_cols * sizeof(int));
+      memcpy(temp_bg_color_buffer[i], bg_color_buffer[i],
+             term_cols * sizeof(unsigned long));
+    }
+    for (int j = 0; j < amount; j++) {
+      // Move all lines up one position
+      for (int y = 0; y < term_rows - 1; y++) {
+        memcpy(terminal_buffer[y], temp_buffer[y + 1], term_cols);
+        memcpy(color_buffer[y], temp_color_buffer[y + 1],
+               term_cols * sizeof(unsigned long));
+        memcpy(attr_buffer[y], temp_attr_buffer[y + 1],
+               term_cols * sizeof(int));
+        memcpy(bg_color_buffer[y], temp_bg_color_buffer[y + 1],
+               term_cols * sizeof(unsigned long));
+      }
+
+      // Clear the bottom line
+      memset(terminal_buffer[term_rows - 1], ' ', term_cols);
+      for (int x = 0; x < term_cols; x++) {
+        color_buffer[term_rows - 1][x] = current_color;
+        attr_buffer[term_rows - 1][x] = current_attr;
+        bg_color_buffer[term_rows - 1][x] = current_bg_color;
+      }
+    }
+  } else {
+    for (int i = 0; i < term_rows; i++) {
+      memcpy(temp_buffer[i], terminal_buffer[i], term_cols * sizeof(char));
+      memcpy(temp_color_buffer[i], color_buffer[i],
+             term_cols * sizeof(unsigned long));
+      memcpy(temp_attr_buffer[i], attr_buffer[i], term_cols * sizeof(int));
+      memcpy(temp_bg_color_buffer[i], bg_color_buffer[i],
+             term_cols * sizeof(unsigned long));
+    }
+    for (int j = 0; j < amount; j++) {
+      int start = (scroll_top - 1);
+      int end = (scroll_bottom - 1);
+      if (start < 0)
+        start = 0;
+      if (end < 0)
+        end = 0;
+      if (end >= term_rows)
+        end = term_rows - 1;
+      // Move all lines up one position
+      for (int y = start; y < end; y++) {
+        memcpy(terminal_buffer[y], temp_buffer[y + 1], term_cols);
+        memcpy(color_buffer[y], temp_color_buffer[y + 1],
+               term_cols * sizeof(unsigned long));
+        memcpy(attr_buffer[y], temp_attr_buffer[y + 1],
+               term_cols * sizeof(int));
+        memcpy(bg_color_buffer[y], temp_bg_color_buffer[y + 1],
+               term_cols * sizeof(unsigned long));
+      }
+
+      // Clear the bottom line
+      memset(terminal_buffer[end], ' ', term_cols);
+      for (int x = 0; x < term_cols; x++) {
+        color_buffer[end][x] = current_color;
+        attr_buffer[end][x] = current_attr;
+        bg_color_buffer[end][x] = current_bg_color;
+      }
+    }
+  }
+
+  for (int i = 0; i < term_rows; i++) {
+    free(temp_buffer[i]);
+    free(temp_color_buffer[i]);
+    free(temp_attr_buffer[i]);
+    free(temp_bg_color_buffer[i]);
+  }
+  free(temp_buffer);
+  free(temp_color_buffer);
+  free(temp_attr_buffer);
+  free(temp_bg_color_buffer);
+  needs_refresh = 1;
+}
+
+static void scroll_region_down(int amount) {
+  char **temp_buffer = NULL;
+  unsigned long **temp_color_buffer = NULL;
+  int **temp_attr_buffer = NULL;
+  unsigned long **temp_bg_color_buffer = NULL;
+
+  temp_buffer = malloc(term_rows * sizeof(char *));
+  temp_color_buffer = malloc(term_rows * sizeof(unsigned long *));
+  temp_attr_buffer = malloc(term_rows * sizeof(int *));
+  temp_bg_color_buffer = malloc(term_rows * sizeof(unsigned long *));
+
+  if (!temp_buffer || !temp_color_buffer || !temp_attr_buffer ||
+      !temp_bg_color_buffer) {
+    fprintf(stderr, "Failed to allocate memory for temp buffers\n");
+    return;
+  }
+  for (int i = 0; i < term_rows; i++) {
+    temp_buffer[i] = malloc(term_cols * sizeof(char));
+    temp_color_buffer[i] = malloc(term_cols * sizeof(unsigned long));
+    temp_attr_buffer[i] = malloc(term_cols * sizeof(int));
+    temp_bg_color_buffer[i] = malloc(term_cols * sizeof(unsigned long));
+
+    if (!temp_buffer[i] || !temp_color_buffer[i] || !temp_attr_buffer[i] ||
+        !temp_bg_color_buffer[i]) {
+      fprintf(stderr, "Failed to allocate memory for temp buffer row\n");
+      free(temp_buffer);
+      free(temp_color_buffer);
+      free(temp_attr_buffer);
+      free(temp_bg_color_buffer);
+      return;
+    }
+  }
+
+  if (scroll_top == 0 && scroll_bottom == 0) {
+    for (int i = 0; i < term_rows; i++) {
+      memcpy(temp_buffer[i], terminal_buffer[i], term_cols * sizeof(char));
+      memcpy(temp_color_buffer[i], color_buffer[i],
+             term_cols * sizeof(unsigned long));
+      memcpy(temp_attr_buffer[i], attr_buffer[i], term_cols * sizeof(int));
+      memcpy(temp_bg_color_buffer[i], bg_color_buffer[i],
+             term_cols * sizeof(unsigned long));
+    }
+    for (int j = 0; j < amount; j++) {
+      // Move all lines down one position
+      for (int y = term_rows - 1; y > 0; y--) {
+        memcpy(terminal_buffer[y], temp_buffer[y - 1], term_cols);
+        memcpy(color_buffer[y], temp_color_buffer[y - 1],
+               term_cols * sizeof(unsigned long));
+        memcpy(attr_buffer[y], temp_attr_buffer[y - 1],
+               term_cols * sizeof(int));
+        memcpy(bg_color_buffer[y], temp_bg_color_buffer[y - 1],
+               term_cols * sizeof(unsigned long));
+      }
+      // Clear the top line
+      memset(terminal_buffer[0], ' ', term_cols);
+      for (int x = 0; x < term_cols; x++) {
+        color_buffer[0][x] = current_color;
+        attr_buffer[0][x] = current_attr;
+        bg_color_buffer[0][x] = current_bg_color;
+      }
+    }
+  } else {
+    for (int i = 0; i < term_rows; i++) {
+      memcpy(temp_buffer[i], terminal_buffer[i], term_cols * sizeof(char));
+      memcpy(temp_color_buffer[i], color_buffer[i],
+             term_cols * sizeof(unsigned long));
+      memcpy(temp_attr_buffer[i], attr_buffer[i], term_cols * sizeof(int));
+      memcpy(temp_bg_color_buffer[i], bg_color_buffer[i],
+             term_cols * sizeof(unsigned long));
+    }
+    for (int j = 0; j < amount; j++) {
+      int start = (scroll_top - 1);
+      int end = (scroll_bottom - 1);
+      if (start < 0)
+        start = 0;
+      if (end < 0)
+        end = 0;
+      if (end >= term_rows)
+        end = term_rows - 1;
+
+      // Move all lines down one position
+      for (int y = end; y > start; y--) {
+        memcpy(terminal_buffer[y], temp_buffer[y - 1], term_cols);
+        memcpy(color_buffer[y], temp_color_buffer[y - 1],
+               term_cols * sizeof(unsigned long));
+        memcpy(attr_buffer[y], temp_attr_buffer[y - 1],
+               term_cols * sizeof(int));
+        memcpy(bg_color_buffer[y], temp_bg_color_buffer[y - 1],
+               term_cols * sizeof(unsigned long));
+      }
+
+      // Clear the top line
+      memset(terminal_buffer[start], ' ', term_cols);
+      for (int x = 0; x < term_cols; x++) {
+        color_buffer[start][x] = current_color;
+        attr_buffer[start][x] = current_attr;
+        bg_color_buffer[start][x] = current_bg_color;
+      }
+    }
+  }
+  for (int i = 0; i < term_rows; i++) {
+    free(temp_buffer[i]);
+    free(temp_color_buffer[i]);
+    free(temp_attr_buffer[i]);
+    free(temp_bg_color_buffer[i]);
+  }
+  free(temp_buffer);
+  free(temp_color_buffer);
+  free(temp_attr_buffer);
+  free(temp_bg_color_buffer);
+  needs_refresh = 1;
+}
+
 // Alternative buffer visual:
 //
 // Normal buffer:             Alternate buffer:
@@ -453,7 +683,8 @@ static void scroll_up(void) {
 // saved_terminal = backup of normal buffer
 // saved_colors/attrs = backup of attributes
 // using_alternate = tracks which buffer is active
-static void handle_alternate_buffer(const char *buf, int *idx, int max_len) {
+static void handle_alternate_buffer(const char *buf, int *idx, int max_len,
+                                    Window window) {
   char num_buf[32] = {0};
   size_t num_idx = 0;
 
@@ -488,6 +719,8 @@ static void handle_alternate_buffer(const char *buf, int *idx, int max_len) {
               bg_color_buffer[i] = calloc(term_cols, sizeof(unsigned long));
             }
             using_alternate = 1;
+            needs_refresh = 1;
+            draw_terminal(display, window);
           }
         } else if (using_alternate) {
           for (int i = 0; i < term_rows; i++) {
@@ -506,6 +739,8 @@ static void handle_alternate_buffer(const char *buf, int *idx, int max_len) {
           bg_color_buffer = saved_colors;
           saved_terminal = NULL;
           using_alternate = 0;
+          needs_refresh = 1;
+          draw_terminal(display, window);
         }
         break;
       case 1048: // Save/restore cursor
@@ -537,6 +772,8 @@ static void handle_alternate_buffer(const char *buf, int *idx, int max_len) {
               bg_color_buffer[i] = calloc(term_cols, sizeof(unsigned long));
             }
             using_alternate = 1;
+            needs_refresh = 1;
+            draw_terminal(display, window);
           }
         } else if (using_alternate) {
           for (int i = 0; i < term_rows; i++) {
@@ -557,6 +794,8 @@ static void handle_alternate_buffer(const char *buf, int *idx, int max_len) {
           cursor_x = saved_cursor_x;
           cursor_y = saved_cursor_y;
           using_alternate = 0;
+          needs_refresh = 1;
+          draw_terminal(display, window);
         }
         break;
       }
@@ -583,7 +822,7 @@ static unsigned long get_bright_ansi_color(int index) {
 //   34 = Blue     35 = Magenta  36 = Cyan    37 = White
 // 0 sets everything back to plain white
 // P.S. yes I had to google this up
-static void parse_ansi_code(const char *buf, int *idx, int max_len) {
+static void parse_ansi_code(const char *buf, int *idx, int max_len, Window window) {
   char num_buf[32] = {0};
   int params[32] = {0};
   size_t num_idx = 0;
@@ -592,7 +831,7 @@ static void parse_ansi_code(const char *buf, int *idx, int max_len) {
 
   // Handle '?' prefix for private sequences
   if (buf[*idx] == '?') {
-    handle_alternate_buffer(buf, idx, max_len);
+    handle_alternate_buffer(buf, idx, max_len, window);
     return;
   }
 
@@ -678,6 +917,54 @@ static void parse_ansi_code(const char *buf, int *idx, int max_len) {
       needs_refresh = 1;
     }
     break;
+  case 'r': // Set scrolling region
+    if (param_idx == 0) {
+      scroll_top = 0; // Entire terminal
+      scroll_bottom = 0;
+    } else if (param_idx == 1) {
+      scroll_top = (params[0] <= 0)
+                       ? 1
+                       : (params[0] > term_rows ? term_rows : params[0]);
+      scroll_bottom = 0;
+    } else if (param_idx >= 2) {
+      scroll_top = (params[0] <= 0)
+                       ? 1
+                       : (params[0] > term_rows ? term_rows : params[0]);
+      scroll_bottom = (params[1] <= 0)
+                          ? term_rows
+                          : (params[1] > term_rows ? term_rows : params[1]);
+
+      // if top is bigger than bottom, swap values
+      if (scroll_top > scroll_bottom) {
+        int tmp = scroll_top;
+        scroll_top = scroll_bottom;
+        scroll_bottom = tmp;
+        break;
+      case 'S': // Scroll up
+        scroll_region_up(params[0] == 0 ? 1 : params[0]);
+        needs_refresh = 1;
+        break;
+      case 'T': // Scroll down
+        scroll_region_down(params[0] == 0 ? 1 : params[0]);
+        needs_refresh = 1;
+        break;
+      case 'E': // Cursor next line
+        cursor_x = 0;
+        cursor_y += params[0] ? params[0] : 1;
+        if (cursor_y >= term_rows) {
+          cursor_y = term_rows - 1;
+        }
+        break;
+      case 'F': // Cursor line before
+        cursor_x = 0;
+        cursor_y -= params[0] ? params[0] : 1;
+        if (cursor_y < 0) {
+          cursor_y = 0;
+        }
+        break;
+      }
+    }
+    break;
   case 'm': // Handling of text
     for (int i = 0; i < param_idx; i++) {
       if (params[i] == 0) { // Reset Everything
@@ -722,7 +1009,7 @@ static void parse_ansi_code(const char *buf, int *idx, int max_len) {
   }
 }
 
-static int master_cb(int fd, void *data) {
+static int master_cb(int fd, void *data, Window window) {
   if (!terminal_buffer || !color_buffer || !attr_buffer || !bg_color_buffer)
     return 0;
   char buf[4096];
@@ -740,7 +1027,7 @@ static int master_cb(int fd, void *data) {
   if (bytes_read > 0) {
     for (int i = 0; i < bytes_read; i++) {
       if (buf[i] == '\033' && i + 1 < bytes_read && buf[i + 1] == '[') {
-        parse_ansi_code(buf, &i, bytes_read);
+        parse_ansi_code(buf, &i, bytes_read, window);
         continue;
       }
       if (buf[i] == '\n') {
@@ -1043,7 +1330,7 @@ int main(void) {
     FD_ZERO(&fds);
     FD_SET(master, &fds);
     if (select(master + 1, &fds, NULL, NULL, &tv) > 0) {
-      master_cb(master, &ctx);
+      master_cb(master, &ctx, window);
     }
 
     check_refresh(display, window);