Introduce DISTRHO_UI_DEFAULT_WIDTH/HEIGHT macros, useful in VST2/3

distrho/DistrhoInfo.hpp

@@ -618,6 +618,24 @@ START_NAMESPACE_DISTRHO
  */
 #define DISTRHO_UI_CUSTOM_WIDGET_TYPE
 
+/**
+   Default UI width to use when creating initial and temporary windows.@n
+   Setting this macro allows to skip a temporary UI from being created in certain VST2 and VST3 hosts.
+   (which would normally be done for knowing the UI size before host creates a window for it)
+
+   When this macro is defined, the companion DISTRHO_UI_DEFAULT_HEIGHT macro must be defined as well.
+ */
+#define DISTRHO_UI_DEFAULT_WIDTH 300
+
+/**
+   Default UI height to use when creating initial and temporary windows.@n
+   Setting this macro allows to skip a temporary UI from being created in certain VST2 and VST3 hosts.
+   (which would normally be done for knowing the UI size before host creates a window for it)
+
+   When this macro is defined, the companion DISTRHO_UI_DEFAULT_WIDTH macro must be defined as well.
+ */
+#define DISTRHO_UI_DEFAULT_HEIGHT 300
+
 /**
    Whether the %UI uses NanoVG for drawing instead of the default raw OpenGL calls.@n
    When enabled your %UI instance will subclass @ref NanoWidget instead of @ref Widget.

distrho/src/DistrhoPluginChecks.h

@@ -183,6 +183,17 @@
 # define DISTRHO_PLUGIN_HAS_UI 0
 #endif
 
+// -----------------------------------------------------------------------
+// Make sure both default width and height are provided
+
+#if defined(DISTRHO_UI_DEFAULT_WIDTH) && !defined(DISTRHO_UI_DEFAULT_HEIGHT)
+# error DISTRHO_UI_DEFAULT_WIDTH is defined but DISTRHO_UI_DEFAULT_HEIGHT is not
+#endif
+
+#if defined(DISTRHO_UI_DEFAULT_HEIGHT) && !defined(DISTRHO_UI_DEFAULT_WIDTH)
+# error DISTRHO_UI_DEFAULT_HEIGHT is defined but DISTRHO_UI_DEFAULT_WIDTH is not
+#endif
+
 // -----------------------------------------------------------------------
 // Prevent users from messing about with DPF internals
 

distrho/src/DistrhoPluginVST2.cpp

@@ -575,17 +575,25 @@ public:
             }
             else
             {
+                double scaleFactor = fLastScaleFactor;
+               #if defined(DISTRHO_UI_DEFAULT_WIDTH) && defined(DISTRHO_UI_DEFAULT_HEIGHT)
+                fVstRect.right = DISTRHO_UI_DEFAULT_WIDTH;
+                fVstRect.bottom = DISTRHO_UI_DEFAULT_HEIGHT;
+                if (d_isZero(scaleFactor))
+                    scaleFactor = 1.0;
+               #else
                 UIExporter tmpUI(nullptr, 0, fPlugin.getSampleRate(),
                                  nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, d_nextBundlePath,
-                                 fPlugin.getInstancePointer(), fLastScaleFactor);
-                fVstRect.right  = tmpUI.getWidth();
+                                 fPlugin.getInstancePointer(), scaleFactor);
+                fVstRect.right = tmpUI.getWidth();
                 fVstRect.bottom = tmpUI.getHeight();
-# ifdef DISTRHO_OS_MAC
-                const double scaleFactor = tmpUI.getScaleFactor();
+                scaleFactor = tmpUI.getScaleFactor();
+                tmpUI.quit();
+               #endif
+               #ifdef DISTRHO_OS_MAC
                 fVstRect.right /= scaleFactor;
                 fVstRect.bottom /= scaleFactor;
-# endif
-                tmpUI.quit();
+               #endif
             }
             *(ERect**)ptr = &fVstRect;
             return 1;

distrho/src/DistrhoUI.cpp

@@ -202,13 +202,23 @@ UI::PrivateData::createNextWindow(UI* const ui, const uint width, const uint hei
  * UI */
 
 UI::UI(const uint width, const uint height, const bool automaticallyScaleAndSetAsMinimumSize)
-    : UIWidget(UI::PrivateData::createNextWindow(this, width, height)),
+    : UIWidget(UI::PrivateData::createNextWindow(this,
+              #ifdef DISTRHO_UI_DEFAULT_WIDTH
+               width == 0 ? DISTRHO_UI_DEFAULT_WIDTH :
+              #endif
+               width,
+              #ifdef DISTRHO_UI_DEFAULT_WIDTH
+               height == 0 ? DISTRHO_UI_DEFAULT_WIDTH :
+              #endif
+               height)),
       uiData(UI::PrivateData::s_nextPrivateData)
 {
 #if !DISTRHO_PLUGIN_HAS_EXTERNAL_UI
     if (width != 0 && height != 0)
     {
+       #ifndef DISTRHO_UI_DEFAULT_WIDTH
         Widget::setSize(width, height);
+       #endif
 
         if (automaticallyScaleAndSetAsMinimumSize)
             setGeometryConstraints(width, height, true, true, true);

distrho/src/DistrhoUIVST3.cpp

@@ -1473,19 +1473,26 @@ struct dpf_plugin_view : v3_plugin_view_cpp {
 
         view->sizeRequestedBeforeBeingAttached = true;
 
-        const float lastScaleFactor = view->scale != nullptr ? view->scale->scaleFactor : 0.0f;
+        double scaleFactor = view->scale != nullptr ? view->scale->scaleFactor : 0.0;
+       #if defined(DISTRHO_UI_DEFAULT_WIDTH) && defined(DISTRHO_UI_DEFAULT_HEIGHT)
+        rect->right = DISTRHO_UI_DEFAULT_WIDTH;
+        rect->bottom = DISTRHO_UI_DEFAULT_HEIGHT;
+        if (d_isZero(scaleFactor))
+            scaleFactor = 1.0;
+       #else
         UIExporter tmpUI(nullptr, 0, view->sampleRate,
                          nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, d_nextBundlePath,
-                         view->instancePointer, lastScaleFactor);
-        rect->left = rect->top = 0;
-        rect->right  = tmpUI.getWidth();
+                         view->instancePointer, scaleFactor);
+        rect->right = tmpUI.getWidth();
         rect->bottom = tmpUI.getHeight();
+        scaleFactor = tmpUI.getScaleFactor();
+        tmpUI.quit();
+       #endif
+        rect->left = rect->top = 0;
        #ifdef DISTRHO_OS_MAC
-        const double scaleFactor = tmpUI.getScaleFactor();
         rect->right /= scaleFactor;
         rect->bottom /= scaleFactor;
        #endif
-        tmpUI.quit();
 
         return V3_OK;
     }