mini-curve-display: new extension (#455)

Author: abique

include/clap/all.h

@@ -7,6 +7,7 @@
 
 #include "ext/draft/extensible-audio-ports.h"
 #include "ext/draft/gain-adjustment-metering.h"
+#include "ext/draft/mini-curve-display.h"
 #include "ext/draft/project-location.h"
 #include "ext/draft/resource-directory.h"
 #include "ext/draft/scratch-memory.h"

include/clap/ext/draft/mini-curve-display.h

@@ -0,0 +1,74 @@
+#pragma once
+
+#include "../../plugin.h"
+
+// This extension allows a host to render a small curve provided by the plugin.
+// A useful application is to render an EQ frequency response in the DAW mixer view.
+
+static CLAP_CONSTEXPR const char CLAP_EXT_MINI_CURVE_DISPLAY[] = "clap.mini-curve-display/1";
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct clap_plugin_mini_curve_display {
+   // Renders the curve into the data buffer.
+   // The value 0 will be at the bottom of the curve and UINT16_MAX will be at the top.
+   // The value at index 0 will be the leftmost and the value at index data_size -1 will be the
+   // rightmost.
+   // [main-thread]
+   bool(CLAP_ABI *render)(clap_plugin_t *plugin, uint16_t *data, uint32_t data_size);
+
+   // Tells the plugin if the curve is currently observed or not.
+   // When it isn't observed render() can't be called.
+   //
+   // When is_obseverd becomes true, the curve content and axis name are implicitely invalidated. So
+   // the plugin don't need to call host->changed.
+   //
+   // [main-thread]
+   void(CLAP_ABI *set_observed)(clap_plugin_t *plugin, bool is_observed);
+
+   // Retriev the axis name.
+   // Returns true on success, if the name capacity was sufficient.
+   // [main-thread]
+   bool(CLAP_ABI *get_axis_name)(clap_plugin_t *plugin,
+                                 char          *x_name,
+                                 char          *y_name,
+                                 uint32_t       name_capacity);
+} clap_plugin_mini_curve_display_t;
+
+enum clap_mini_curve_display_change_flags {
+   // Informs the host that the curve content changed.
+   // Can only be called if the curve is observed and is static.
+   CLAP_MINI_CURVE_DISPLAY_CURVE_CHANGED = 1 << 0,
+
+   // Informs the host that the curve axis name changed.
+   // Can only be called if the curve is observed.
+   CLAP_MINI_CURVE_DISPLAY_AXIS_NAME_CHANGED = 1 << 1,
+};
+
+typedef struct clap_host_mini_curve_display {
+   // Mark the curve as being static or dynamic.
+   // The curve is initially considered as static, though the plugin should explicitely
+   // initialize this state.
+   //
+   // When static, the curve changes will be notified by calling host->changed().
+   // When dynamic, the curve is constantly changing and the host is expected to
+   // periodically re-render.
+   //
+   // [main-thread]
+   void(CLAP_ABI *set_dynamic)(clap_host_t *host, bool is_dynamic);
+
+   // Informs the host that the curve content changed.
+   // Can only be called if the curve is observed and is static.
+   // [main-thread]
+   void(CLAP_ABI *curve_changed)(clap_host_t *host);
+
+   // See clap_mini_curve_display_change_flags
+   // [main-thread]
+   void(CLAP_ABI *changed)(clap_host_t *host, uint32_t flags);
+} clap_host_mini_curve_display_t;
+
+#ifdef __cplusplus
+}
+#endif