clap

gui.h (9873B)

---

 #pragma once
 
 #include "../plugin.h"
 
 /// @page GUI
 ///
 /// This extension defines how the plugin will present its GUI.
 ///
 /// There are two approaches:
 /// 1. the plugin creates a window and embeds it into the host's window
 /// 2. the plugin creates a floating window
 ///
 /// Embedding the window gives more control to the host, and feels more integrated.
 /// Floating window are sometimes the only option due to technical limitations.
 ///
 /// The Embedding protocol is by far the most common, supported by all hosts to date,
 /// and a plugin author should support at least that case.
 ///
 /// Showing the GUI works as follow:
 ///  1. clap_plugin_gui->is_api_supported(), check what can work
 ///  2. clap_plugin_gui->create(), allocates gui resources
 ///  3. if the plugin window is floating
 ///  4.    -> clap_plugin_gui->set_transient()
 ///  5.    -> clap_plugin_gui->suggest_title()
 ///  6. else
 ///  7.    -> clap_plugin_gui->set_scale()
 ///  8.    -> clap_plugin_gui->can_resize()
 ///  9.    -> if resizable and has known size from previous session, clap_plugin_gui->set_size()
 /// 10.    -> else clap_plugin_gui->get_size(), gets initial size
 /// 11.    -> clap_plugin_gui->set_parent()
 /// 12. clap_plugin_gui->show()
 /// 13. clap_plugin_gui->hide()/show() ...
 /// 14. clap_plugin_gui->destroy() when done with the gui
 ///
 /// Resizing the window (initiated by the plugin, if embedded):
 /// 1. Plugins calls clap_host_gui->request_resize()
 /// 2. If the host returns true the new size is accepted,
 ///    the host doesn't have to call clap_plugin_gui->set_size().
 ///    If the host returns false, the new size is rejected.
 ///
 /// Resizing the window (drag, if embedded)):
 /// 1. Only possible if clap_plugin_gui->can_resize() returns true
 /// 2. Mouse drag -> new_size
 /// 3. clap_plugin_gui->adjust_size(new_size) -> working_size
 /// 4. clap_plugin_gui->set_size(working_size)
 
 static CLAP_CONSTEXPR const char CLAP_EXT_GUI[] = "clap.gui";
 
 // If your windowing API is not listed here, please open an issue and we'll figure it out.
 // https://github.com/free-audio/clap/issues/new
 
 // uses physical size
 // embed using https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-setparent
 static const CLAP_CONSTEXPR char CLAP_WINDOW_API_WIN32[] = "win32";
 
 // uses logical size, don't call clap_plugin_gui->set_scale()
 static const CLAP_CONSTEXPR char CLAP_WINDOW_API_COCOA[] = "cocoa";
 
 // uses physical size
 // embed using https://specifications.freedesktop.org/xembed-spec/xembed-spec-latest.html
 static const CLAP_CONSTEXPR char CLAP_WINDOW_API_X11[] = "x11";
 
 // uses physical size
 // embed is currently not supported, use floating windows
 static const CLAP_CONSTEXPR char CLAP_WINDOW_API_WAYLAND[] = "wayland";
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 typedef void         *clap_hwnd;
 typedef void         *clap_nsview;
 typedef unsigned long clap_xwnd;
 
 // Represent a window reference.
 typedef struct clap_window {
    const char *api; // one of CLAP_WINDOW_API_XXX
    union {
       clap_nsview cocoa;
       clap_xwnd   x11;
       clap_hwnd   win32;
       void       *ptr; // for anything defined outside of clap
    };
 } clap_window_t;
 
 // Information to improve window resizing when initiated by the host or window manager.
 typedef struct clap_gui_resize_hints {
    bool can_resize_horizontally;
    bool can_resize_vertically;
 
    // if both horizontal and vertical resize are available, do we preserve the
    // aspect ratio, and if so, what is the width x height aspect ratio to preserve.
    // These flags are unused if can_resize_horizontally or vertically are false,
    // and ratios are unused if preserve is false.
    bool     preserve_aspect_ratio;
    uint32_t aspect_ratio_width;
    uint32_t aspect_ratio_height;
 } clap_gui_resize_hints_t;
 
 // Size (width, height) is in pixels; the corresponding windowing system extension is
 // responsible for defining if it is physical pixels or logical pixels.
 typedef struct clap_plugin_gui {
    // Returns true if the requested gui api is supported, either in floating (plugin-created)
    // or non-floating (embedded) mode.
    // [main-thread]
    bool(CLAP_ABI *is_api_supported)(const clap_plugin_t *plugin, const char *api, bool is_floating);
 
    // Returns true if the plugin has a preferred api.
    // The host has no obligation to honor the plugin preference, this is just a hint.
    // The const char **api variable should be explicitly assigned as a pointer to
    // one of the CLAP_WINDOW_API_ constants defined above, not strcopied.
    // [main-thread]
    bool(CLAP_ABI *get_preferred_api)(const clap_plugin_t *plugin,
                                      const char         **api,
                                      bool                *is_floating);
 
    // Create and allocate all resources necessary for the gui.
    //
    // If is_floating is true, then the window will not be managed by the host. The plugin
    // can set its window to stays above the parent window, see set_transient().
    // api may be null or blank for floating window.
    //
    // If is_floating is false, then the plugin has to embed its window into the parent window, see
    // set_parent().
    //
    // After this call, the GUI may not be visible yet; don't forget to call show().
    //
    // Returns true if the GUI is successfully created.
    // [main-thread]
    bool(CLAP_ABI *create)(const clap_plugin_t *plugin, const char *api, bool is_floating);
 
    // Free all resources associated with the gui.
    // [main-thread]
    void(CLAP_ABI *destroy)(const clap_plugin_t *plugin);
 
    // Set the absolute GUI scaling factor, and override any OS info.
    // Should not be used if the windowing api relies upon logical pixels.
    //
    // If the plugin prefers to work out the scaling factor itself by querying the OS directly,
    // then ignore the call.
    //
    // scale = 2 means 200% scaling.
    //
    // Returns true if the scaling could be applied
    // Returns false if the call was ignored, or the scaling could not be applied.
    // [main-thread]
    bool(CLAP_ABI *set_scale)(const clap_plugin_t *plugin, double scale);
 
    // Get the current size of the plugin UI.
    // clap_plugin_gui->create() must have been called prior to asking the size.
    //
    // Returns true if the plugin could get the size.
    // [main-thread]
    bool(CLAP_ABI *get_size)(const clap_plugin_t *plugin, uint32_t *width, uint32_t *height);
 
    // Returns true if the window is resizeable (mouse drag).
    // [main-thread & !floating]
    bool(CLAP_ABI *can_resize)(const clap_plugin_t *plugin);
 
    // Returns true if the plugin can provide hints on how to resize the window.
    // [main-thread & !floating]
    bool(CLAP_ABI *get_resize_hints)(const clap_plugin_t *plugin, clap_gui_resize_hints_t *hints);
 
    // If the plugin gui is resizable, then the plugin will calculate the closest
    // usable size which fits in the given size.
    // This method does not change the size.
    //
    // Returns true if the plugin could adjust the given size.
    // [main-thread & !floating]
    bool(CLAP_ABI *adjust_size)(const clap_plugin_t *plugin, uint32_t *width, uint32_t *height);
 
    // Sets the window size.
    //
    // Returns true if the plugin could resize its window to the given size.
    // [main-thread & !floating]
    bool(CLAP_ABI *set_size)(const clap_plugin_t *plugin, uint32_t width, uint32_t height);
 
    // Embeds the plugin window into the given window.
    //
    // Returns true on success.
    // [main-thread & !floating]
    bool(CLAP_ABI *set_parent)(const clap_plugin_t *plugin, const clap_window_t *window);
 
    // Set the plugin floating window to stay above the given window.
    //
    // Returns true on success.
    // [main-thread & floating]
    bool(CLAP_ABI *set_transient)(const clap_plugin_t *plugin, const clap_window_t *window);
 
    // Suggests a window title. Only for floating windows.
    //
    // [main-thread & floating]
    void(CLAP_ABI *suggest_title)(const clap_plugin_t *plugin, const char *title);
 
    // Show the window.
    //
    // Returns true on success.
    // [main-thread]
    bool(CLAP_ABI *show)(const clap_plugin_t *plugin);
 
    // Hide the window, this method does not free the resources, it just hides
    // the window content. Yet it may be a good idea to stop painting timers.
    //
    // Returns true on success.
    // [main-thread]
    bool(CLAP_ABI *hide)(const clap_plugin_t *plugin);
 } clap_plugin_gui_t;
 
 typedef struct clap_host_gui {
    // The host should call get_resize_hints() again.
    // [thread-safe & !floating]
    void(CLAP_ABI *resize_hints_changed)(const clap_host_t *host);
 
    // Request the host to resize the client area to width, height.
    // Return true if the new size is accepted, false otherwise.
    // The host doesn't have to call set_size().
    //
    // Note: if not called from the main thread, then a return value simply means that the host
    // acknowledged the request and will process it asynchronously. If the request then can't be
    // satisfied then the host will call set_size() to revert the operation.
    // [thread-safe & !floating]
    bool(CLAP_ABI *request_resize)(const clap_host_t *host, uint32_t width, uint32_t height);
 
    // Request the host to show the plugin gui.
    // Return true on success, false otherwise.
    // [thread-safe]
    bool(CLAP_ABI *request_show)(const clap_host_t *host);
 
    // Request the host to hide the plugin gui.
    // Return true on success, false otherwise.
    // [thread-safe]
    bool(CLAP_ABI *request_hide)(const clap_host_t *host);
 
    // The floating window has been closed, or the connection to the gui has been lost.
    //
    // If was_destroyed is true, then the host must call clap_plugin_gui->destroy() to acknowledge
    // the gui destruction.
    // [thread-safe]
    void(CLAP_ABI *closed)(const clap_host_t *host, bool was_destroyed);
 } clap_host_gui_t;
 
 #ifdef __cplusplus
 }
 #endif