add support for http://lv2plug.in/ns/ext/port-props/#rangeSteps

diff --git a/libs/ardour/lv2_plugin.cc b/libs/ardour/lv2_plugin.cc
index 0d43895ea2b1f36a7abba456d954d282a7aee4ac..f33c9db6ac4ec678680c305c7d66813f6cb187dc 100644 (file)
--- a/libs/ardour/lv2_plugin.cc
+++ b/libs/ardour/lv2_plugin.cc
@@ -130,6 +130,7 @@ public:
        LilvNode* ext_expensive;
        LilvNode* ext_causesArtifacts;
        LilvNode* ext_notAutomatic;
+       LilvNode* ext_rangeSteps;
        LilvNode* lv2_AudioPort;
        LilvNode* lv2_ControlPort;
        LilvNode* lv2_InputPort;
@@ -1934,6 +1935,8 @@ LV2Plugin::get_parameter_descriptor(uint32_t which, ParameterDescriptor& desc) c
        lilv_port_get_range(_impl->plugin, port, &def, &min, &max);
        portunits = lilv_port_get_value(_impl->plugin, port, _world.units_unit);
 
+       LilvNode* steps   = lilv_port_get(_impl->plugin, port, _world.ext_rangeSteps);
+
        // TODO: Once we can rely on lilv 0.18.0 being present,
        // load_parameter_descriptor() can be used for ports as well
        desc.integer_step = lilv_port_has_property(_impl->plugin, port, _world.lv2_integer);
@@ -1959,9 +1962,34 @@ LV2Plugin::get_parameter_descriptor(uint32_t which, ParameterDescriptor& desc) c
 
        desc.update_steps();
 
+       if (steps) {
+               //override auto-calculated steps in update_steps()
+               float s = lilv_node_as_float (steps);
+               const float delta = desc.upper - desc.lower;
+
+               desc.step = desc.smallstep = (delta / s);
+               desc.largestep = std::min ((delta / 5.0f), 10.f * desc.smallstep);
+
+               if (desc.logarithmic) {
+                       // TODO marry AutomationControl::internal_to_interface () with
+                       // http://lv2plug.in/ns/ext/port-props/#rangeSteps
+                       desc.smallstep = desc.smallstep / logf(s);
+                       desc.step      = desc.step      / logf(s);
+                       desc.largestep = desc.largestep / logf(s);
+               } else if (desc.integer_step) {
+                       desc.smallstep = 1.0;
+                       desc.step      = std::max(1.f, rintf (desc.step));
+                       desc.largestep = std::max(1.f, rintf (desc.largestep));
+               }
+               DEBUG_TRACE(DEBUG::LV2, string_compose("parameter %1 small: %2, step: %3 largestep: %4\n",
+                                       which, desc.smallstep, desc.step, desc.largestep));
+       }
+
+
        lilv_node_free(def);
        lilv_node_free(min);
        lilv_node_free(max);
+       lilv_node_free(steps);
        lilv_nodes_free(portunits);
 
        return 0;
@@ -2819,6 +2847,7 @@ LV2World::LV2World()
        ext_expensive      = lilv_new_uri(world, LV2_PORT_PROPS__expensive);
        ext_causesArtifacts= lilv_new_uri(world, LV2_PORT_PROPS__causesArtifacts);
        ext_notAutomatic   = lilv_new_uri(world, LV2_PORT_PROPS__notAutomatic);
+       ext_rangeSteps     = lilv_new_uri(world, LV2_PORT_PROPS__rangeSteps);
        lv2_AudioPort      = lilv_new_uri(world, LILV_URI_AUDIO_PORT);
        lv2_ControlPort    = lilv_new_uri(world, LILV_URI_CONTROL_PORT);
        lv2_InputPort      = lilv_new_uri(world, LILV_URI_INPUT_PORT);
@@ -2910,6 +2939,7 @@ LV2World::~LV2World()
        lilv_node_free(lv2_InputPort);
        lilv_node_free(lv2_ControlPort);
        lilv_node_free(lv2_AudioPort);
+       lilv_node_free(ext_rangeSteps);
        lilv_node_free(ext_notAutomatic);
        lilv_node_free(ext_causesArtifacts);
        lilv_node_free(ext_expensive);

diff --git a/libs/ardour/parameter_descriptor.cc b/libs/ardour/parameter_descriptor.cc
index e28dbecd3586afec3875d71c4da92db4e29ee176..880adfb162424b2b3d8e76eaa1b849d160480a3a 100644 (file)
--- a/libs/ardour/parameter_descriptor.cc
+++ b/libs/ardour/parameter_descriptor.cc
@@ -158,6 +158,9 @@ ParameterDescriptor::update_steps()
                step      = slider_position_to_gain(largestep / 10.0);
                smallstep = step;
        } else {
+               /* note that LV2Plugin::get_parameter_descriptor ()
+                * overrides this is lv2:rangeStep is set for a port.
+                */
                const float delta = upper - lower;
 
                /* 30 happens to be the total number of steps for a fader with default