Commit 059daff

#include "knobs.h"

#include <cmath>

#include <cstdlib>

#include <imgui.h>

#include <imgui_internal.h>

#include <utility>

namespace ImGuiKnobs {

namespace detail {

std::pair<ImVec2, ImVec2> bezier_arc(ImVec2 center, ImVec2 start, ImVec2 end) {

auto ax = start[0] - center[0];

auto ay = start[1] - center[1];

auto bx = end[0] - center[0];

auto by = end[1] - center[1];

auto q1 = ax * ax + ay * ay;

auto q2 = q1 + ax * bx + ay * by;

auto k2 = (4.0f / 3.0f) * (sqrtf((2.0f * q1 * q2)) - q2) / (ax * by - ay * bx);

return {

{center[0] + ax - k2 * ay, center[1] + ay + k2 * ax},

{center[0] + bx + k2 * by, center[1] + by - k2 * bx},

};

}

void draw_arc1(ImVec2 center, float radius, float start_angle, float end_angle, float thickness, ImColor color, int num_segments) {

ImVec2 start = {

center[0] + cosf(start_angle) * radius,

center[1] + sinf(start_angle) * radius,

};

ImVec2 end = {

center[0] + cosf(end_angle) * radius,

center[1] + sinf(end_angle) * radius,

};

auto arc = bezier_arc(center, start, end);

auto *draw_list = ImGui::GetWindowDrawList();

draw_list->AddBezierCurve(start, arc.first, arc.second, end, color, thickness, num_segments);

}

void draw_arc(ImVec2 center, float radius, float start_angle, float end_angle, float thickness, ImColor color, int num_segments, int bezier_count) {

// Overlap and angle of ends of bezier curves needs work, only looks good when not transperant

auto overlap = thickness * radius * 0.00001f * M_PI;

auto delta = end_angle - start_angle;

auto bez_step = 1.0f / bezier_count;

auto mid_angle = start_angle + overlap;

for (auto i = 0; i < bezier_count - 1; i++) {

auto mid_angle2 = delta * bez_step + mid_angle;

draw_arc1(

center,

radius,

mid_angle - overlap,

mid_angle2 + overlap,

thickness,

color,

num_segments);

mid_angle = mid_angle2;

}

draw_arc1(

center,

radius,

mid_angle - overlap,

end_angle,

thickness,

color,

num_segments);

}

bool knob_control(const char *id, float *p_value, float v_min, float v_max, float v_default, float radius) {

ImGui::InvisibleButton(id, {radius * 2.0f, radius * 2.0f});

auto value_changed = false;

auto is_active = ImGui::IsItemActive();

auto delta = ImGui::GetMouseDragDelta(ImGuiMouseButton_Left, 0.0001f);

const auto &io = ImGui::GetIO();

// Maybe this should be configurable

auto speed = io.KeyShift ? 2000.0f : 200.0f;

if (ImGui::IsMouseDoubleClicked(ImGuiMouseButton_Left) && is_active) {

*p_value = v_default;

value_changed = true;

} else if (is_active && delta[1] != 0.0) {

auto step = (v_max - v_min) / speed;

*p_value -= delta[1] * step;

if (*p_value < v_min) {

*p_value = v_min;

}

if (*p_value > v_max) {

*p_value = v_max;

}

value_changed = true;

// There may be a way to do this without using this

ImGui::ResetMouseDragDelta(ImGuiMouseButton_Left);

}

return value_changed;

}

knob::knob(const char *_label, float *_p_value, float _v_min, float _v_max, float _v_default, float _radius) {

auto _angle_min = M_PI * 0.75;

auto _angle_max = M_PI * 2.25;

auto _t = (*_p_value - _v_min) / (_v_max - _v_min);

auto _angle = _angle_min + (_angle_max - _angle_min) * _t;

auto _value_changed = false;

auto _screen_pos = ImGui::GetCursorScreenPos();

_value_changed = knob_control(_label, _p_value, _v_min, _v_max, _v_default, _radius);

label = _label;

p_value = _p_value;

v_min = _v_min;

v_max = _v_max;

v_default = _v_default;

radius = _radius;

screen_pos = _screen_pos;

value_changed = _value_changed;

center = {screen_pos[0] + radius, screen_pos[1] + radius};

is_active = ImGui::IsItemActive();

is_hovered = ImGui::IsItemHovered();

angle_min = _angle_min;

angle_max = _angle_max;

t = _t;

angle = _angle;

angle_cos = cosf(angle);

angle_sin = sinf(angle);

}

void knob::draw_dot(float size, float radius, float angle, color_set color, bool filled, int segments) {

auto dot_size = size * this->radius;

auto dot_radius = radius * this->radius;

ImGui::GetWindowDrawList()->AddCircleFilled(

{

center[0] + cosf(angle) * dot_radius,

center[1] + sinf(angle) * dot_radius,

},

dot_size,

is_active ? color.active : (is_hovered ? color.hovered : color.base),

segments);

}

void knob::draw_tick(float start, float end, float width, float angle, color_set color) {

auto tick_start = start * radius;

auto tick_end = end * radius;

auto angle_cos = cosf(angle);

auto angle_sin = sinf(angle);

ImGui::GetWindowDrawList()->AddLine(

{

center[0] + angle_cos * tick_end,

center[1] + angle_sin * tick_end,

},

{

center[0] + angle_cos * tick_start,

center[1] + angle_sin * tick_start,

},

is_active ? color.active : (is_hovered ? color.hovered : color.base),

width * radius);

}

void knob::draw_circle(float size, color_set color, bool filled, int segments) {

auto circle_radius = size * radius;

ImGui::GetWindowDrawList()->AddCircleFilled(

center,

circle_radius,

is_active ? color.active : (is_hovered ? color.hovered : color.base));

}

void knob::draw_arc(float radius, float size, float start_angle, float end_angle, color_set color, int segments, int bezier_count) {

auto track_radius = radius * this->radius;

auto track_size = size * this->radius * 0.5f + 0.0001f;

detail::draw_arc(

center,

track_radius,

start_angle,

end_angle,

track_size,

is_active ? color.active : (is_hovered ? color.hovered : color.base),

segments,

bezier_count);

}

knob knob_with_drag(const char *label, float *p_value, float v_min, float v_max, float v_default, const char *format, float size) {

ImGui::PushID(label);

auto width = size == 0 ? ImGui::GetTextLineHeight() * 4.0f : size * ImGui::GetIO().FontGlobalScale;

ImGui::PushItemWidth(width);

// Draw title

auto title_size = ImGui::CalcTextSize(label, NULL, false, width);

auto old_cursor_pos = ImGui::GetCursorPos();

// Center title

ImGui::SetCursorPos({old_cursor_pos[0] + (width - title_size[0]) * 0.5f, old_cursor_pos[1]});

ImGui::Text("%s", label);

// Reset cursor X

ImGui::SetCursorPosX(old_cursor_pos[0]);

knob k(label, p_value, v_min, v_max, v_default, width * 0.5f);

ImGui::DragScalar("###knob_drag", ImGuiDataType_Float, p_value, (v_max - v_min) / 1000.f, &v_min, &v_max, format);

ImGui::PopItemWidth();

ImGui::PopID();

return k;

}

color_set GetPrimaryColorSet() {

auto *colors = ImGui::GetStyle().Colors;

return {colors[ImGuiCol_ButtonActive], colors[ImGuiCol_ButtonHovered], colors[ImGuiCol_ButtonHovered]};

}

color_set GetSecondaryColorSet() {

auto *colors = ImGui::GetStyle().Colors;

auto active = colors[ImGuiCol_ButtonActive] * ImVec4(0.5f, 0.5f, 0.5f, 1.f);

auto hovered = colors[ImGuiCol_ButtonHovered] * ImVec4(0.5f, 0.5f, 0.5f, 1.f);

return {active, hovered, hovered};

}

color_set GetTrackColorSet() {

auto *colors = ImGui::GetStyle().Colors;

return {colors[ImGuiCol_FrameBg], colors[ImGuiCol_FrameBg], colors[ImGuiCol_FrameBg]};

}

}// namespace detail

// Knob implementations

KNOB_WIDGET(WiperKnob) {

auto knob = detail::knob_with_drag(title, p_value, v_min, v_max, 0, format, size);

knob.draw_circle(0.7, detail::GetSecondaryColorSet(), true, 32);

knob.draw_arc(0.8, 0.41, knob.angle_min, knob.angle_max, detail::GetTrackColorSet(), 16, 2);

if (knob.t > 0.01) {

knob.draw_arc(0.8, 0.43, knob.angle_min, knob.angle, detail::GetPrimaryColorSet(), 16, 2);

}

return knob.value_changed;

}

KNOB_WIDGET(WiperOnlyKnob) {

auto knob = detail::knob_with_drag(title, p_value, v_min, v_max, 0, format, size);

knob.draw_arc(0.8, 0.41, knob.angle_min, knob.angle_max, detail::GetTrackColorSet(), 32, 2);

if (knob.t > 0.01) {

knob.draw_arc(0.8, 0.43, knob.angle_min, knob.angle, detail::GetPrimaryColorSet(), 16, 2);

}

return knob.value_changed;

}

KNOB_WIDGET(WiperDotKnob) {

auto knob = detail::knob_with_drag(title, p_value, v_min, v_max, 0, format, size);

knob.draw_circle(0.6, detail::GetSecondaryColorSet(), true, 32);

knob.draw_arc(0.85, 0.41, knob.angle_min, knob.angle_max, detail::GetTrackColorSet(), 16, 2);

knob.draw_dot(0.1, 0.85, knob.angle, detail::GetPrimaryColorSet(), true, 12);

return knob.value_changed;

}

KNOB_WIDGET(TickKnob) {

auto knob = detail::knob_with_drag(title, p_value, v_min, v_max, 0, format, size);

knob.draw_circle(0.7, detail::GetSecondaryColorSet(), true, 32);

knob.draw_tick(0.4, 0.7, 0.08, knob.angle, detail::GetPrimaryColorSet());

return knob.value_changed;

}

KNOB_WIDGET(DotKnob) {

auto knob = detail::knob_with_drag(title, p_value, v_min, v_max, 0, format, size);

knob.draw_circle(0.85, detail::GetSecondaryColorSet(), true, 32);

knob.draw_dot(0.12, 0.6, knob.angle, detail::GetPrimaryColorSet(), true, 12);

return knob.value_changed;

}

KNOB_WIDGET(SpaceKnob) {

auto knob = detail::knob_with_drag(title, p_value, v_min, v_max, 0, format, size);

knob.draw_circle(0.3 - knob.t * 0.1, detail::GetSecondaryColorSet(), true, 16);

if (knob.t > 0.01) {

knob.draw_arc(0.4, 0.15, knob.angle_min - 1.0, knob.angle - 1.0, detail::GetPrimaryColorSet(), 16, 2);

knob.draw_arc(0.6, 0.15, knob.angle_min + 1.0, knob.angle + 1.0, detail::GetPrimaryColorSet(), 16, 2);

knob.draw_arc(0.8, 0.15, knob.angle_min + 3.0, knob.angle + 3.0, detail::GetPrimaryColorSet(), 16, 2);

}

return knob.value_changed;

}

KNOB_WIDGET(SteppedKnob, int steps) {

auto knob = detail::knob_with_drag(title, p_value, v_min, v_max, 0, format, size);

for (auto n = 0.f; n < steps; n++) {

auto a = n / (steps - 1);

auto angle = knob.angle_min + (knob.angle_max - knob.angle_min) * a;

knob.draw_tick(0.7, 0.9, 0.04, angle, detail::GetPrimaryColorSet());

}

knob.draw_circle(0.6, detail::GetSecondaryColorSet(), true, 32);

knob.draw_dot(0.12, 0.4, knob.angle, detail::GetPrimaryColorSet(), true, 12);

return knob.value_changed;

}

}// namespace ImGuiKnobs