Abstract class for visualizing (i.e. drawing) a stopwatch. More...

#include <stopwatch.h>

Inheritance diagram for flutter::StopwatchVisualizer:

Public Member Functions
	StopwatchVisualizer (const Stopwatch &stopwatch)

virtual	~StopwatchVisualizer ()=default

virtual void	Visualize (DlCanvas *canvas, const DlRect &rect) const =0
	Renders the stopwatch as a graph.

	FML_DISALLOW_COPY_AND_ASSIGN (StopwatchVisualizer)

Protected Member Functions
double	UnitFrameInterval (double time_ms) const
	Converts a raster time to a unit interval.

double	UnitHeight (double time_ms, double max_height) const
	Converts a raster time to a unit height.

fml::Milliseconds	GetFrameBudget () const

Protected Attributes
const Stopwatch &	stopwatch_

fml::Milliseconds	frame_budget_

Detailed Description

Abstract class for visualizing (i.e. drawing) a stopwatch.

Note: This was originally folded into the |Stopwatch| class, but was separated out to make it easier to change the underlying implementation (which relied directly on Skia, not showing on Impeller: https://github.com/flutter/flutter/issues/126009).

Definition at line 96 of file stopwatch.h.

Constructor & Destructor Documentation

◆ StopwatchVisualizer()

flutter::StopwatchVisualizer::StopwatchVisualizer ( const Stopwatch & stopwatch )

inlineexplicit

Definition at line 98 of file stopwatch.h.

      : stopwatch_(stopwatch) {
    // Looking up the frame budget from the stopwatch delegate class may call
    // into JNI or make platform calls which are slow. This value is safe to
    // cache since the StopwatchVisualizer is recreated on each frame.
    frame_budget_ = stopwatch_.GetFrameBudget();
  }

References frame_budget_, flutter::Stopwatch::GetFrameBudget(), and stopwatch_.

◆ ~StopwatchVisualizer()

virtual flutter::StopwatchVisualizer::~StopwatchVisualizer ( )

virtualdefault

Member Function Documentation

◆ FML_DISALLOW_COPY_AND_ASSIGN()

flutter::StopwatchVisualizer::FML_DISALLOW_COPY_AND_ASSIGN ( StopwatchVisualizer )

◆ GetFrameBudget()

fml::Milliseconds flutter::StopwatchVisualizer::GetFrameBudget ( ) const

inlineprotected

Definition at line 123 of file stopwatch.h.

123{ return frame_budget_; }

References frame_budget_.

Referenced by flutter::DlStopwatchVisualizer::Visualize().

◆ UnitFrameInterval()

double flutter::StopwatchVisualizer::UnitFrameInterval ( double time_ms ) const

protected

Converts a raster time to a unit interval.

Definition at line 54 of file stopwatch.cc.

                                                                         {
  return raster_time_ms / frame_budget_.count();
}

References frame_budget_.

Referenced by UnitHeight(), and flutter::DlStopwatchVisualizer::Visualize().

◆ UnitHeight()

double flutter::StopwatchVisualizer::UnitHeight	(	double	time_ms,
		double	max_height
	)		const

protected

Converts a raster time to a unit height.

Definition at line 58 of file stopwatch.cc.

                                                                       {
  double unit_height = UnitFrameInterval(raster_time_ms) / max_unit_interval;
  if (unit_height > 1.0) {
    unit_height = 1.0;
  }
  return unit_height;
}