ladybird/Userland/Applications/Piano/WaveWidget.cpp
Fabian Neundorf 413e212ea8 Piano: Cache buffers in Track and WaveWidget
The Track itself caches the Samples after each processing step which
allows it to be queried without the need to process it every time.

This result is queried by the WaveWidget which then caches the result to
prevent unnecessary heap allocations every paint event.
2023-08-04 12:56:27 +02:00

68 lines
2.5 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2019-2020, William McPherson <willmcpherson2@gmail.com>
* Copyright (c) 2022, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include "WaveWidget.h"
#include "TrackManager.h"
#include <AK/NumericLimits.h>
#include <AK/StdLibExtras.h>
#include <LibGUI/Painter.h>
WaveWidget::WaveWidget(TrackManager& track_manager)
: m_track_manager(track_manager)
{
}
int WaveWidget::sample_to_y(float sample, float sample_max) const
{
if (sample_max < 1.0f)
sample_max = 1.0f;
sample_max *= rescale_factor;
double percentage = static_cast<double>(sample) / static_cast<double>(sample_max);
double portion_of_half_height = percentage * ((frame_inner_rect().height() - 1) / 2.0);
double y = (frame_inner_rect().height() / 2.0) + portion_of_half_height;
return y;
}
void WaveWidget::paint_event(GUI::PaintEvent& event)
{
GUI::Painter painter(*this);
painter.fill_rect(frame_inner_rect(), Color::Black);
painter.translate(frame_thickness(), frame_thickness());
Color left_wave_color = left_wave_colors[m_track_manager.current_track()->synth()->wave()];
Color right_wave_color = right_wave_colors[m_track_manager.current_track()->synth()->wave()];
m_track_manager.current_track()->write_cached_signal_to(m_samples.span());
double width_scale = static_cast<double>(frame_inner_rect().width()) / m_samples.size();
auto const maximum = Audio::Sample::max_range(m_samples.span());
int prev_x = 0;
int prev_y_left = sample_to_y(m_samples[0].left, maximum.left);
int prev_y_right = sample_to_y(m_samples[0].right, maximum.right);
painter.set_pixel({ prev_x, prev_y_left }, left_wave_color);
painter.set_pixel({ prev_x, prev_y_right }, right_wave_color);
for (size_t x = 1; x < m_samples.size(); ++x) {
int y_left = sample_to_y(m_samples[x].left, maximum.left);
int y_right = sample_to_y(m_samples[x].right, maximum.right);
Gfx::IntPoint point1_left(prev_x * width_scale, prev_y_left);
Gfx::IntPoint point2_left(x * width_scale, y_left);
painter.draw_line(point1_left, point2_left, left_wave_color);
Gfx::IntPoint point1_right(prev_x * width_scale, prev_y_right);
Gfx::IntPoint point2_right(x * width_scale, y_right);
painter.draw_line(point1_right, point2_right, right_wave_color);
prev_x = x;
prev_y_left = y_left;
prev_y_right = y_right;
}
GUI::Frame::paint_event(event);
}