imgui-plot
An improved plot widget for Dear ImGui, aimed at displaying audio data
TOC
Screenshots
Displaying waveform and spectrum:
Custom tooltip:
Selection example:
Rationale
The PlotLines() function in Dear ImGui is nice and simple, but it does lack some basic features, such as grids, logarithmic scaling, custom tooltips etc.
My work involves handling lots of waveforms and their spectrums, so I decided to extend PlotLines() with these features to display this data in a nice(r) way.
Usage
Instead of feeding all the parameters into plot function via its arguments, I decided that, with all the configurability, it would be cleaner to have a struct PlotConfig with all the neccessary stuff in it. See imgui_plot.h for its description.
Simple usecase:
ImGui::PlotConfig conf;
conf.values.xs = x_data; // this line is optional
conf.values.ys = y_data;
conf.values.count = data_count;
conf.scale.min = -1;
conf.scale.max = 1;
conf.tooltip.show = true;
conf.tooltip.format = "x=%.2f, y=%.2f";
conf.grid_x.show = true;
conf.grid_y.show = true;
conf.frame_size = ImVec2(400, 400);
conf.line_thickness = 2.f;
ImGui::Plot("plot", conf);Selection example (gif above):
constexpr size_t buf_size = 512;
static float x_data[buf_size];
static float y_data1[buf_size];
static float y_data2[buf_size];
static float y_data3[buf_size];
void generate_data() {
constexpr float sampling_freq = 44100;
constexpr float freq = 500;
for (size_t i = 0; i < buf_size; ++i) {
const float t = i / sampling_freq;
x_data[i] = t;
const float arg = 2 * M_PI * freq * t;
y_data1[i] = sin(arg);
y_data2[i] = y_data1[i] * -0.6 + sin(2 * arg) * 0.4;
y_data3[i] = y_data2[i] * -0.6 + sin(3 * arg) * 0.4;
}
}
void draw_multi_plot() {
static const float* y_data[] = { y_data1, y_data2, y_data3 };
static ImU32 colors[3] = { ImColor(0, 255, 0), ImColor(255, 0, 0), ImColor(0, 0, 255) };
static uint32_t selection_start = 0, selection_length = 0;
ImGui::Begin("Example plot", nullptr, ImGuiWindowFlags_AlwaysAutoResize);
// Draw first plot with multiple sources
ImGui::PlotConfig conf;
conf.values.xs = x_data;
conf.values.count = buf_size;
conf.values.ys_list = y_data; // use ys_list to draw several lines simultaneously
conf.values.ys_count = 3;
conf.values.colors = colors;
conf.scale.min = -1;
conf.scale.max = 1;
conf.tooltip.show = true;
conf.grid_x.show = true;
conf.grid_x.size = 128;
conf.grid_x.subticks = 4;
conf.grid_y.show = true;
conf.grid_y.size = 0.5f;
conf.grid_y.subticks = 5;
conf.selection.show = true;
conf.selection.start = &selection_start;
conf.selection.length = &selection_length;
conf.frame_size = ImVec2(buf_size, 200);
ImGui::Plot("plot1", conf);
// Draw second plot with the selection
// reset previous values
conf.values.ys_list = nullptr;
conf.selection.show = false;
// set new ones
conf.values.ys = y_data3;
conf.values.offset = selection_start;
conf.values.count = selection_length;
conf.line_thickness = 2.f;
ImGui::Plot("plot2", conf);
ImGui::End();
}
Installation
Just copy include/imgui_plot.h and src/imgui_plot.cpp to where your imgui is, and it should work like that.
CMake
Alternatively, you can use FetchContent like this:
include(FetchContent)
FetchContent_Declare(
imgui_plot
GIT_REPOSITORY https://github.com/soulthreads/imgui-plot.git
GIT_TAG v0.1.0
EXCLUDE_FROM_ALL
)
FetchContent_GetProperties(imgui_plot)
if(NOT imgui_plot_POPULATED)
FetchContent_Populate(imgui_plot)
add_subdirectory(${imgui_plot_SOURCE_DIR} ${imgui_plot_BINARY_DIR})
endif()and then just link imgui_plot into your application. If you have ImGui located not in {repo}/imgui you can set IMGUI_INCLUDE_DIR variable to the according value.
FAQ
How do I do x?
If something isn't obvious or your think my design is bad, please file away an issue, I'll take a look at it.
If you want to have some new feature, issues and PRs are welcome too.