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My Thoughts, Trials and Adventures

Getting Started with GTK4 on Windows

Posted at — Sep 4, 2021

Introduction

This article guides how to set up and write applications with GTK4 on the windows operating system.

GTK

https://www.gtk.org/assets/img/logo-gtk-sm.png

GTK (formerly GIMP ToolKit then GTK+) is a free and open-source cross-platform widget toolkit for creating graphical user interfaces (GUIs).

[wikipedia] [Official Website]

Setup

GTK can also be compiled with MSVC / Visual Studio. while compiling with MSVC makes it more compatible with the Visual Studio ecosystem, it limits the libraries we can include in our project. mixing MSYS2 and MSVC libraries cause problems.

To compile with MSVC:

meson setup -Dmedia-gstreamer=disabled -Dbuild-tests=disabled build
meson compile -C build
meson install -C build

Refer: Build and run GTK 4 applications with Visual Studio

MSYS2

MSYS2 is a collection of tools and libraries providing you with an easy-to-use environment for building, installing, and running native Windows software.

  1. Install the latest version MSYS2 from their website.
  2. Navigate to C:\msys2\ and launch mingw64.exe.
  3. to update available repositories and packages, run: pacman -Syyu
  4. install gtk4, gcc (llvm should work too!), pkg-config: pacman -S mingw-w64-x86_64-gcc mingw-w64-x86_64-gtk4 mingw-w64-x86_64-pkg-config

Now add Mingw64 directories to System Path so that windows can find them: add the following to the system path:

C:\\msys64\\mingw64\\include
C:\\msys64\\mingw64\\bin
C:\\msys64\\mingw64\\lib

https://i.imgur.com/9nD9ZCp.png

  1. We also need to pass the output of pkg-config to gcc while compiling. firstly, open CMD and get the output of pkg-config --cflags --libs gtk4.

It will produce something like this:

-mfpmath=sse -msse -msse2 -pthread -mms-bitfields -IC:/msys64/mingw64/include/gtk-4.0 -IC:/msys64/mingw64/include -IC:/msys64/mingw64/include/pango-1.0 -IC:/msys64/mingw64/include/harfbuzz -IC:/msys64/mingw64/include/pango-1.0 -IC:/msys64/mingw64/include/fribidi -IC:/msys64/mingw64/include -IC:/msys64/mingw64/include/gdk-pixbuf-2.0 -IC:/msys64/mingw64/include/libpng16 -IC:/msys64/mingw64/include -IC:/msys64/mingw64/include/cairo -IC:/msys64/mingw64/include/lzo -IC:/msys64/mingw64/include -IC:/msys64/mingw64/include/freetype2 -IC:/msys64/mingw64/include/libpng16 -IC:/msys64/mingw64/include/harfbuzz -IC:/msys64/mingw64/include -IC:/msys64/mingw64/include/pixman-1 -IC:/msys64/mingw64/include -IC:/msys64/mingw64/include/graphene-1.0 -IC:/msys64/mingw64/lib/graphene-1.0/include -IC:/msys64/mingw64/include -IC:/msys64/mingw64/include/glib-2.0 -IC:/msys64/mingw64/lib/glib-2.0/include -IC:/msys64/mingw64/include -LC:/msys64/mingw64/lib -lgtk-4 -lpangowin32-1.0 -lpangocairo-1.0 -lpango-1.0 -lharfbuzz -lgdk_pixbuf-2.0 -lcairo-gobject -lcairo -lvulkan -lgraphene-1.0 -lgio-2.0 -lgobject-2.0 -lglib-2.0 -lintl

copy the output and add it as a System Variable (I saved it as GTK4-PKG-CONFIG):

https://i.imgur.com/oxcoJbA.png

Visual Studio Code

I prefer Visual studio code for all my coding tasks. You can get the latest version of Visual studio code from their website.

  1. Create a new folder and open it in VSCode.
  2. create a new file .vscode/c_cpp_properties.json and put the following in it:
{
    "configurations": [
        {
            "name": "Win32",
            "includePath": [
                "${workspaceFolder}\\**",
                "C:\\msys64\\mingw64\\include\\**",
                "C:\\msys64\\mingw64\\lib\\glib-2.0\\include",
                "C:\\msys64\\mingw64\\lib\\graphene-1.0\\include"
            ]
        }
    ],
    "version": 4
}

notice the C:\msys64\mingw64\include\**, C:\msys64\mingw64\lib\glib-2.0\include and C:\msys64\mingw64\lib\graphene-1.0\include. these are the header files we need for auto complete suggestions which will make our life easier.

  1. create a new file, hello_world.c file, and paste the Hello World C program from GTK.org:
// Include gtk
#include <gtk/gtk.h>

static void on_activate (GtkApplication *app) {
  // Create a new window
  GtkWidget *window = gtk_application_window_new (app);
  // Create a new button
  GtkWidget *button = gtk_button_new_with_label ("Hello, World!");
  // When the button is clicked, close the window passed as an argument
  g_signal_connect_swapped (button, "clicked", G_CALLBACK (gtk_window_close), window);
  gtk_window_set_child (GTK_WINDOW (window), button);
  gtk_window_present (GTK_WINDOW (window));
}

int main (int argc, char *argv[]) {
  // Create a new application
  GtkApplication *app = gtk_application_new ("com.example.GtkApplication",
                                             G_APPLICATION_FLAGS_NONE);
  g_signal_connect (app, "activate", G_CALLBACK (on_activate), NULL);
  return g_application_run (G_APPLICATION (app), argc, argv);
}

  1. Compile the program: gcc hello_world.c -o hello_world.exe -mwindows %GTK4-PKG-CONFIG%
  2. Run the program by clicking on generated .exe file.

https://i.imgur.com/oHf7ZqG.png

Debugging

Setting up debugging enviroment is quite easy. Defaults should just work fine as long as you select the correct compiler when prompted, I’ve added -mwindows to compile flags for good measure.

.vscode/launch.json

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "gcc.exe - Build and debug active file",
            "type": "cppdbg",
            "request": "launch",
            "program": "${fileDirname}\\${fileBasenameNoExtension}.exe",
            "args": [],
            "stopAtEntry": false,
            "cwd": "${fileDirname}",
            "environment": [],
            "externalConsole": false,
            "MIMode": "gdb",
            "miDebuggerPath": "C:\\msys64\\mingw64\\bin\\gdb.exe",
            "setupCommands": [
                {
                    "description": "Enable pretty-printing for gdb",
                    "text": "-enable-pretty-printing",
                    "ignoreFailures": true
                }
            ],
            "preLaunchTask": "C/C++: gcc.exe build active file"
        }
    ]
}

.vscode/tasks.json

{
    "tasks": [
        {
            "type": "cppbuild",
            "label": "C/C++: gcc.exe build active file",
            "command": "C:\\msys64\\mingw64\\bin\\gcc.exe",
            "args": [
                "-g",
                "${file}",
                "-o",
                "${fileDirname}\\${fileBasenameNoExtension}.exe",
                "-mwindows",
                "%GTK4-PKG-CONFIG%"
            ],
            "options": {
                "cwd": "${fileDirname}"
            },
            "problemMatcher": [
                "$gcc"
            ],
            "group": {
                "kind": "build",
                "isDefault": true
            },
            "detail": "Task generated by Debugger."
        }
    ],
    "version": "2.0.0"
}

Add breakpoint wherever you wish and debug away!

https://i.imgur.com/QVZD3Bq.png

A bit complicated example…

Let’s make things a little complicated, suppose we want to make an application to show the current time using Win32 API, this is how it can be done:

#include <stdio.h>
#include <windows.h>
#include <gtk/gtk.h>


void get_current_time(GtkButton *btn, GtkLabel *label){

  SYSTEMTIME st, lt;
  printf("Button Clicked!\n");
    
  GetSystemTime(&st);
  GetLocalTime(&lt);

  char buf[1024];
  sprintf(buf, "%02d:%02d:%02d %d/%d/%d", st.wHour, st.wMinute, st.wSecond, st.wDay, st.wMonth, st.wYear);
  gtk_label_set_label(label, buf);
  
}

static void on_activate (GtkApplication *app) {
  // Create a new window
  GtkWidget *window = gtk_application_window_new (app);

  GtkWidget *box = gtk_box_new(GTK_ORIENTATION_VERTICAL, 4);

  GtkWidget *label = gtk_label_new("Hello GTK!");
  GtkWidget *btn = gtk_button_new_with_label("Get Current Time");
  gtk_widget_set_margin_start(GTK_WIDGET(btn), 4);
  gtk_widget_set_margin_end(GTK_WIDGET(btn), 4);
  g_signal_connect_after(btn , "clicked", (GCallback)get_current_time, label);

  gtk_box_append(GTK_BOX(box), label);
  gtk_box_append(GTK_BOX(box), btn);

  gtk_window_set_child (GTK_WINDOW (window), box);
  gtk_window_present (GTK_WINDOW (window));
}

int main (int argc, char *argv[]) {
  // Create a new application
  GtkApplication *app = gtk_application_new ("com.example.GtkApplication",
                                             G_APPLICATION_FLAGS_NONE);
  g_signal_connect (app, "activate", G_CALLBACK (on_activate), NULL);
  return g_application_run (G_APPLICATION (app), argc, argv);
}

Compile the program with:

gcc whatismytime.c -o whatismytime -mwindows %GTK4-PKG-CONFIG%

https://i.imgur.com/YURHuEM.png

Meson Build System

Available on Github.

Meson is the official build system used by GNOME. I’ve taken the above example and made it into a Meson Project.

tree
├── meson.build
├── README.md
└── src
    ├── meson.build
    └── whatismytime.c

1 directory, 4 files

meson uses ninja to build/compile. get the latest ninja from their Github page and add the extracted directory to System Path.

to build:

meson build
ninja -C build

and then navigate to build/src and execute whatismytime.exe