feat(layouts): 实现 fair/fullscreen/maximize 内置布局

src/layouts/fair.c

@@ -0,0 +1,63 @@
+#include "layouts/fair.h"
+
+#include <math.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <zdwm/layout.h>
+
+bool fair(const zdwm_layout_ctx_t *ctx, zdwm_layout_result_t *out) {
+  auto windows = ctx->window_ids;
+  auto count   = (int32_t)ctx->window_count;
+  if (!windows || !count) return false;
+
+  zdwm_layout_result_reset(out);
+
+  auto columns = (int32_t)floor(sqrt(count));
+  if (columns * (columns + 1) <= count) ++columns;
+
+  auto rows_in_other_cols = count / columns;
+  auto rows_in_main_col   = count - (columns - 1) * rows_in_other_cols;
+  while (rows_in_main_col > rows_in_other_cols) {
+    ++rows_in_other_cols;
+    rows_in_main_col = count - (columns - 1) * rows_in_other_cols;
+  }
+
+  auto workarea            = &ctx->workarea;
+  auto width_avg           = workarea->width / columns;
+  auto width_for_main_col  = workarea->width - (columns - 1) * width_avg;
+  auto width_for_other_col = width_avg;
+
+  int32_t row = 0, col = 0, row_count;
+  int32_t x = workarea->x, y = workarea->y;
+  for (int32_t i = 0; i < count; ++i) {
+    int32_t width;
+
+    if (i < rows_in_main_col) {
+      row       = i;
+      width     = width_for_main_col;
+      row_count = rows_in_main_col;
+    } else {
+      width     = width_for_other_col;
+      row_count = rows_in_other_cols;
+      if (((i - rows_in_main_col) % row_count) == 0) {
+        col++;
+        row  = 0;
+        x   += col == 1 ? width_for_main_col : width_for_other_col;
+        y    = workarea->y;
+      }
+    }
+
+    auto h_avg              = workarea->height / row_count;
+    auto h_main             = workarea->height - h_avg * (row_count - 1);
+    auto height             = row == 0 ? h_main : h_avg;
+    zdwm_layout_item_t item = {
+      .window_id = windows[i],
+      .rect      = {.x = x, .y = y, .width = width, .height = height}
+    };
+    zdwm_layout_result_push(out, item);
+
+    y += height;
+  }
+
+  return true;
+}