VIUP is a work-in-progress V wrapper for the C-based cross-platform UI library, IUP . The aim of this library is to provide a thorough implementation of IUP in V. The implmentation is faithful to the original API but takes some liberties to provide a native "V" feel and modernizes some of the calls.

Windows Gallery Example Linux (Ubuntu) Gallery Example


  • image
    • load image
    • convert image to native
    • convert native to image
  • basic controls
  • containers
  • dialogs
  • gl
    • gl rendering
    • gl controls
  • scintilla
  • plot
  • extra controls
  • clipboard
  • browser


  1. Download the appropriate runtime libraries for your Operating system:
  2. If using image functions, download IM runtime libraries:

Windows install

Copy all applicable DLLs from Zip to binary directory. By default, only iup.dll is required. If using image functions, iup_im.dll is required as well as all of the DLLs frmo the IM library.

Windows App Manifest

Windows UI apps need to be built with a Manifest. This manifest includes details about the app such as the name, version, and characteristics. VIUP includes a basic manifest with the gallery that can be easily modified. The generated manifest.syso needs to be in the directory during build but does not need to be distributed with your application.

To update the manifest:

cd winmanifest windres -i resources.rc -o manifest.syso -O coff

Copy manifest.syso to application directory.

Note: Currently running v . or v run . will not find the .syso file correctly. To include it in your project, add a #flag windows "path\\to\\file\\manifest.syso to the top of your application.

Linux install

Extract runtime libraries to a folder and run sudo ./install to install libraries.

Libraries Path

I've noticed in testing that the libraries are installed to /usr/lib64 . It does not appear that they are picked up by the compiler there. Copying from that folder to /usr/lib resolves the problem. This may not be necessary in all cases.

Notes about dependencies

This repo comes with a copy of the headers for the version of IUP that it was developed against (3.30), but does not ship with the runtime libraries. It is not necessary to get the IM library runtime if you do not plan to use it in your application.

By default VIUP only initializes the subsystems that are imported. For example, importing just viup only initializes the standard dialogs, containers, and components.

If an extension library is loaded ( viup.image ), the required runtime binaries must be installed or provided along with the build.


This repo comes with a simple application that demos all of the available controls. This app is available in the "examples/gallery". It requires the IM libraries. Once all runtime libraries are in the folder, run the example with v run . .

Using VIUP

One of the strengths of IUP is that is it a very simple library. All controls are instances of &Control and share the same methods, though not all methods are applicable to a Control. Adjusting settings for a control is as simple as calling set_attr or providing the attributes when initializing the Control.

Here's a basic example of initializing a simple window:

    dialog(viup.scroll(hbox), "title=Control Gallery")   // Create our dialog with "Control Gallery" as the title and a scrollable Control
    .set_handle("MainWindow")                            // Define a global ID for our Window
    .set_menu("app_menu", menu)                          // Set an app menu if applicable
    .show_xy(,           // Display dialog in center of screen


VIUP should work with V's autofree, however, there are a few situations that can cause crashes. If a Control is accessed by calling get_focused or get_handle , the resulting variable, once it goes out of scope, will free the control that was restored by those functions. This may crash the application. For now if those methods are used, add [manualfree] to the method and call free() on the Controls within as necessary.


All controls can be passed attributes as the last parameters when creating a Control. Any amount of attributes can provided. Attributes can adjust the various characteristics of a Control such as the title, value(s), background or foreground colors, control sub-type, sizing, etc.

Not all available attributes apply to each control. If an invalid attribute is provided it is actually accessible via get_attr but will not affect the control itself. Read up more on attributes in the IUP Documentation .


    "List",               // control 'name'
    "1=Combo Item 1",     // Attr 1: Slot 1 is 'Combo Item 1'
    "2=Combo Item 2",     // Attr 2: Slot 2 is 'Combo Item 2'
    "3=Combo Item 3",     // ....
    "4=Combo Item 4",     // ....
    "dropdown=yes",       // Attr 5: List is a dropdown
    "expand=horizontal",  // Attr 6: Expand horizontally
    "value=1"             // Attr 7: Set default value to Slot 1

Callbacks & Events

All controls have callback methods available for various events. Each callback method starts with on_ and can be quickly chained to add multiple callbacks.


viup.button("Button", "action").on_action(button_clicked)

fn button_clicked(control &viup.Control) viup.FuncResult {
    viup.message("Button Click", "Button clicked!")
    return .cont

In the example above, a Button control is initialized with "Button" for the title. An action callback is added with on_action(button_clicked) . button_clicked is an ActionFunc callback and is automatically called when the button is clicked. VIUP mirrors the callbacks that IUP provides pretty closely, typically adding Func on the end for consistency.

The majority of callback functions can return a viup.FuncResult . This result can be one of the following:

  • cont - continue action
  • close - close the application
  • default - perform default action (may be equivalent to cont in most cases)
  • ignore - ignores event and may stop propagation


Most Control methods will return back the Control when finished. This makes it easy to chain several method calls together.


    )                                            // Create a message dialog with attributes "title", "value", and "dialogtype"
    .popup(viup.Pos.current, viup.Pos.current)   // Popup dialog to user
    .destroy()                                   // Destroy dialog when closed

Example 2:

    .button("Set font...", "", "expand=horizontal") // Create button with "Set font..." as title
    .set_handle("font_btn")                         // Set a handle name
    .on_action(font_button_clicked) // Set a Action callback

Note: Dialogs return back an struct of Dialog . This struct has a few unique functions associated with it (i.e. popup , show , show_xy ). It's not to chain to these methods from regular Control methods.


All dialog, layouts and elements are "Controls" in IUP. As such, they all share common methods that can be utilized by any Control.

Most used component methods:

Method Description
get_attr / set_attr Get or set an attribute value on the control.
set_attrs Used to set multiple attributes in a single call
set_handle Assigns this control a name on the global level. This is typically used in combination with viup.get_handle to restore the control in callbacks or other functions
get_font / set_font Get or set a Font
refresh / refresh_children Trigger a redraw for this component and/or its children

Dialog Controls

Function Description
color_dialog(...attrs) Opens a color picker with optional color palette
dialog(child, attrs) Creates a standard Window or modal dialog
file_dialog(...attrs) Open a file chooser. This can be used to open or save files
font_dialog(...attrs) Opens a font picker
message_dialog(...attrs) Opens a customizable message modal
message(title, message) Shows a generic message box with a standard "OK" button to close

Container Controls

Function Description
background(child, attrs) A simple container element that is designed to have a background color or image
detach_box(child, attrs) Container that is designed to be detachable from the parent container when needed. Can also be reattached.
fill(...attrs) Fills the remaining space for the parent container
flat_frame(child, attrs) Standard frame that allows custom rendering
flat_scroll(child, attrs) Standard scroll that allows custom rendering
frame(child, attrs) Container that puts a border around its children with an optional title
grid(children, attrs) Multi-control container that lays out its children in a table-like design
hbox(children, attrs) Multi-control container that lays out its children in a row
menu(children, attrs) Multi-control container for a dialog's menu items
radio_group(child, attrs) Container is used to group toggle s together into a radio button group
tabs(children, attrs) Multi-control container for tabbed content
vbox(children, attrs) Multi-control container that lays out its children in a column

Standard Controls

Function Description
animated_label(animation, attrs) Creates a control that can display an animation
button(title, action, attrs) Creates a standard button with title for the text
canvas(action, attrs) A control that can be used to render custom content
divider(...attrs) Draws a horizontal or vertical line (horizontal by default)
label(title, attrs) A simple control to show text or images
link(url, title, attrs) Similar to a label, can be used to link to an external source
list(action, attrs) Creates a component that can be used to list multiple values
menu_item(action, attrs) Used in the menu component as a specific action (e.g. "Open File..." or "About")
menu_sep(...attrs) Create a simple horizontal line in a menu
multiline(action, attrs) Creates a multiline chooser component
progress(...attrs) Basic progressbar component
slider(orientation, attrs) Creates a number-line slider component
sub_menu(title, child, attrs) Creates a sub menu component. Sub-menues are children of menu components. Typically structured like: Menu -> Sub-menu -> Menu -> Menu Item.
text(action, attrs) Creates a standard text-input control. Can be set as multi-line, number input, etc.
toggle(title, action, attrs) A radio or checkbox component. Defaults to radio when in a radio_group .

Contributing / Support

This project was developed as a way of improving my understanding of V & C. I will not be providing active support for the project, but I'll happily accept any pull requests. Use at your own discretion!


last May 7