canvas_touch_handler.h

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#ifndef YAZE_APP_GUI_CANVAS_CANVAS_TOUCH_HANDLER_H
#define YAZE_APP_GUI_CANVAS_CANVAS_TOUCH_HANDLER_H
 
#include <string>
 
#include "app/gui/core/touch_input.h"
#include "imgui/imgui.h"
 
namespace yaze {
namespace gui {
 
class CanvasTouchHandler {
 public:
  struct Config {
    // Scale limits
    float min_scale = 0.25f;
    float max_scale = 4.0f;
 
    // Whether touch pan/zoom is enabled
    bool enable_pan = true;
    bool enable_zoom = true;
 
    // Smooth animations
    bool enable_smooth_zoom = true;
    float zoom_smoothing = 0.2f;
 
    // Inertia settings
    bool enable_inertia = true;
    float inertia_deceleration = 0.92f;
    float inertia_min_velocity = 0.5f;
 
    // Canvas boundaries (0 = no limits)
    float max_pan_x = 0.0f;
    float max_pan_y = 0.0f;
    float min_pan_x = 0.0f;
    float min_pan_y = 0.0f;
  };
 
  CanvasTouchHandler() = default;
 
  void Initialize(const std::string& canvas_id = "");
 
  void Update();
 
  bool IsTouchActive() const;
 
  bool IsTouchMode() const;
 
  ImVec2 GetScrollOffset() const { return scroll_offset_; }
 
  float GetScale() const { return current_scale_; }
 
  ImVec2 GetZoomCenter() const { return zoom_center_; }
 
  void SetScrollOffset(ImVec2 offset);
 
  void SetScale(float scale);
 
  void ApplyScrollDelta(ImVec2 delta);
 
  void ApplyZoomDelta(float delta, ImVec2 center);
 
  void Reset();
 
  Config& GetConfig() { return config_; }
  const Config& GetConfig() const { return config_; }
 
  bool WasTapped() const { return was_tapped_; }
 
  bool WasDoubleTapped() const { return was_double_tapped_; }
 
  bool WasLongPressed() const { return was_long_pressed_; }
 
  ImVec2 GetGesturePosition() const { return gesture_position_; }
 
  void ProcessForCanvas(ImVec2 canvas_p0, ImVec2 canvas_sz, bool is_hovered);
 
 private:
  void ProcessGesture(const GestureState& gesture);
  void ProcessInertia();
  void ClampPanToBounds();
 
  std::string canvas_id_;
  Config config_;
 
  // Current canvas transform state
  ImVec2 scroll_offset_ = ImVec2(0, 0);
  float current_scale_ = 1.0f;
  float target_scale_ = 1.0f;
  ImVec2 zoom_center_ = ImVec2(0, 0);
 
  // Inertia state
  ImVec2 inertia_velocity_ = ImVec2(0, 0);
  bool inertia_active_ = false;
 
  // Gesture state for this frame
  bool was_tapped_ = false;
  bool was_double_tapped_ = false;
  bool was_long_pressed_ = false;
  ImVec2 gesture_position_ = ImVec2(0, 0);
 
  // Canvas bounds for gesture processing
  ImVec2 canvas_p0_ = ImVec2(0, 0);
  ImVec2 canvas_sz_ = ImVec2(0, 0);
  bool canvas_hovered_ = false;
 
  // Previous frame state for delta calculations
  ImVec2 prev_pan_offset_ = ImVec2(0, 0);
  float prev_scale_ = 1.0f;
};
 
}  // namespace gui
}  // namespace yaze
 
#endif  // YAZE_APP_GUI_CANVAS_CANVAS_TOUCH_HANDLER_H