healthd: restructure healthd_mode_charger

Refactor drawing code into separate class, and allow for split screen
drawing with offset.

Bug: 63541890
Test: Verify charging mode animation
Change-Id: I6c089460f55b8c2f75f4aa3153a5736f6f434b51
diff --git a/healthd/healthd_draw.h b/healthd/healthd_draw.h
new file mode 100644
index 0000000..6a6ba76
--- /dev/null
+++ b/healthd/healthd_draw.h
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef HEALTHD_DRAW_H
+#define HEALTHD_DRAW_H
+
+#include <linux/input.h>
+#include <minui/minui.h>
+
+#include "animation.h"
+
+using namespace android;
+
+class HealthdDraw {
+ public:
+  // Configures font using given animation.
+  HealthdDraw(animation* anim);
+  virtual ~HealthdDraw();
+
+  // Redraws screen.
+  void redraw_screen(const animation* batt_anim, GRSurface* surf_unknown);
+
+  // Blanks screen if true, unblanks if false.
+  virtual void blank_screen(bool blank);
+
+ protected:
+  virtual void clear_screen();
+
+  // returns the last y-offset of where the surface ends.
+  virtual int draw_surface_centered(GRSurface* surface);
+  // Negative x or y coordinates center text.
+  virtual int draw_text(const GRFont* font, int x, int y, const char* str);
+
+  // Negative x or y coordinates position the text away from the opposite edge
+  // that positive ones do.
+  virtual void determine_xy(const animation::text_field& field,
+                            const int length, int* x, int* y);
+
+  // Draws battery animation, if it exists.
+  virtual void draw_battery(const animation* anim);
+  // Draws clock text, if animation contains text_field data.
+  virtual void draw_clock(const animation* anim);
+  // Draws battery percentage text if animation contains text_field data.
+  virtual void draw_percent(const animation* anim);
+  // Draws charger->surf_unknown or basic text.
+  virtual void draw_unknown(GRSurface* surf_unknown);
+
+  // Pixel sizes of characters for default font.
+  int char_width_;
+  int char_height_;
+
+  // Width and height of screen in pixels.
+  int screen_width_;
+  int screen_height_;
+
+  // Device screen is split vertically.
+  const bool kSplitScreen;
+  // Pixels to offset graphics towards center split.
+  const int kSplitOffset;
+};
+
+#endif  // HEALTHD_DRAW_H