1 files changed, 91 insertions, 0 deletions
diff --git a/pui.c b/pui.c
new file mode 100644
index 0000000..cb89991
--- /dev/null
+++ b/pui.c
@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2020 Mikhail Burakov. This file is part of Pui.
+ *
+ * Pui is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Pui is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Pui.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "pui.h"
+
+#include <assert.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+struct PuiHeader {
+  uint8_t w, h, scale, count;
+};
+
+struct PuiElement {
+  uint8_t x, y, w, h;
+};
+
+static_assert(sizeof(struct PuiHeader) == 4, "Invalid PuiHeader size");
+static_assert(sizeof(struct PuiElement) == 4, "Invalid PuiElement size");
+
+int PuiGetWidth(const void* pui_data) {
+  const struct PuiHeader* pui_header = pui_data;
+  int sx = pui_header->scale >> 4;
+  return pui_header->w << sx;
+}
+
+int PuiGetHeight(const void* pui_data) {
+  const struct PuiHeader* pui_header = pui_data;
+  int sy = pui_header->scale & 0xf;
+  return pui_header->h << sy;
+}
+
+int PuiHitTest(const void* pui_data, int x, int y) {
+  int result = 0;
+  const struct PuiHeader* pui_header = pui_data;
+  x >>= pui_header->scale >> 4;
+  y >>= pui_header->scale & 0xf;
+  int count = pui_header->count >> 4;
+  for (int i = 0; i < count; ++i) {
+    const struct PuiElement* element =
+        (const struct PuiElement*)pui_data + 1 + i;
+    int hit = element->x <= x && x < element->x + element->w &&
+              element->y <= y && y < element->y + element->h;
+    result |= hit << i;
+  }
+  return result;
+}
+
+void PuiRender(const void* pui_data, void* buffer, int stride, int active) {
+  const struct PuiHeader* pui_header = pui_data;
+  int width = pui_header->w << (pui_header->scale >> 4);
+  int height = pui_header->h << (pui_header->scale & 0xf);
+  int elements = pui_header->count >> 4;
+  int colors = pui_header->count & 0xf;
+  const uint32_t* palettes[] = {
+      (const uint32_t*)pui_data + 1 + elements,
+      (const uint32_t*)pui_data + 1 + elements + colors,
+  };
+  const uint8_t* bitmap_data =
+      (const uint8_t*)pui_data + 4 * (1 + elements + 2 * colors);
+  for (int idx = 0, counter = 0, offset = 0; offset < width * height; idx++) {
+    int value = bitmap_data[idx >> 1];
+    if (~idx & 1) value = value >> 4;
+    if (value & 0x8) {
+      counter = counter << 3 | (value & 0x7);
+      continue;
+    }
+    for (counter = counter ? counter + 2 : 1; counter-- > 0; offset++) {
+      int x = offset % width;
+      int y = offset / width;
+      int palette = !!(PuiHitTest(pui_data, x, y) & active);
+      ((uint32_t*)buffer)[x + y * stride] = palettes[palette][value & 0x7];
+    }
+    counter = 0;
+  }
+}