JBR-7158 Wayland: scale with wp_viewport instead of buffer scale

src/java.desktop/unix/classes/sun/awt/wl/WLComponentPeer.java

@@ -119,8 +119,8 @@ public class WLComponentPeer implements ComponentPeer {
     boolean visible = false;
 
     private final Object dataLock = new Object();
-    int width;  // protected by dataLock
-    int height; // protected by dataLock
+    int width;  // in native pixels, protected by dataLock
+    int height; // in native pixels, protected by dataLock
     int wlBufferScale; // protected by dataLock
     double effectiveScale; // protected by dataLock
 
@@ -306,6 +306,7 @@ public class WLComponentPeer implements ComponentPeer {
                     nativeCreateWLPopup(nativePtr, getParentNativePtr(target),
                             thisWidth, thisHeight,
                             parentX + offsetX, parentY + offsetY);
+                    nativeSetSurfaceSize(nativePtr, thisWidth, thisHeight);
                 } else {
                     int xNative = javaUnitsToSurfaceUnits(target.getX());
                     int yNative = javaUnitsToSurfaceUnits(target.getY());
@@ -314,6 +315,7 @@ public class WLComponentPeer implements ComponentPeer {
                             xNative, yNative,
                             isModal, isMaximized, isMinimized,
                             title, WLToolkit.getApplicationID());
+                    nativeSetSurfaceSize(nativePtr, thisWidth, thisHeight);
                 }
                 final long wlSurfacePtr = getWLSurface(nativePtr);
                 WLToolkit.registerWLSurface(wlSurfacePtr, this);
@@ -483,6 +485,9 @@ public class WLComponentPeer implements ComponentPeer {
 
     private void setSizeTo(int newWidth, int newHeight) {
         Dimension newSize = constrainSize(newWidth, newHeight);
+        performLocked(() -> {
+            nativeSetSurfaceSize(nativePtr, javaUnitsToSurfaceUnits(newSize.width), javaUnitsToSurfaceUnits(newSize.height));
+        });
         synchronized (dataLock) {
             this.width = newSize.width;
             this.height = newSize.height;
@@ -523,11 +528,10 @@ public class WLComponentPeer implements ComponentPeer {
     }
 
     /**
-     * Returns the scale of wl_buffer attached to this component's wl_surface.
-     * Buffer coordinate space is linearly scaled wrt the component (or surface)
-     * coordinate space, so component's coordinates have to be translated
-     * to buffers' whenever Wayland protocol requires "buffer-local" coordinates.
-     * See wl_surface.set_buffer_scale in wayland.xml for more details.
+     * Represents the scale ratio of Wayland's backing buffer in pixel units
+     * to surface units. Wayland events are generated in surface units, while
+     * painting should be performed in pixel units.
+     * The ratio is enforced with nativeSetSize().
      */
     int getBufferScale() {
         synchronized(dataLock) {
@@ -1023,6 +1027,7 @@ public class WLComponentPeer implements ComponentPeer {
     private native void nativeRequestFullScreen(long ptr, int wlID);
     private native void nativeRequestUnsetFullScreen(long ptr);
 
+    private native void nativeSetSurfaceSize(long ptr, int width, int height);
     private native void nativeSetWindowGeometry(long ptr, int x, int y, int width, int height);
     private native void nativeSetMinimumSize(long ptr, int width, int height);
     private native void nativeSetMaximumSize(long ptr, int width, int height);

src/java.desktop/unix/classes/sun/java2d/wl/WLSMSurfaceData.java

@@ -49,14 +49,14 @@ public class WLSMSurfaceData extends SurfaceData implements WLSurfaceDataExt {
 
     public native void assignSurface(long surfacePtr);
 
-    private native void initOps(int width, int height, int scale, int backgroundRGB, int wlShmFormat, boolean perfCountersEnabled);
+    private native void initOps(int width, int height, int backgroundRGB, int wlShmFormat, boolean perfCountersEnabled);
     private static native void initIDs();
 
     static {
         initIDs();
     }
 
-    private WLSMSurfaceData(WLComponentPeer peer, SurfaceType surfaceType, ColorModel colorModel, int scale, int wlShmFormat, boolean perfCountersEnabled) {
+    private WLSMSurfaceData(WLComponentPeer peer, SurfaceType surfaceType, ColorModel colorModel, int wlShmFormat, boolean perfCountersEnabled) {
         super(surfaceType, colorModel);
         this.peer = peer;
 
@@ -68,10 +68,10 @@ public class WLSMSurfaceData extends SurfaceData implements WLSurfaceDataExt {
         int height = peer.getBufferHeight();
 
         if (log.isLoggable(PlatformLogger.Level.FINE)) {
-            log.fine(String.format("Shared memory surface data %dx%d x%d scale, format %d", width, height, scale, wlShmFormat));
+            log.fine(String.format("Shared memory surface data %dx%d, format %d", width, height, wlShmFormat));
         }
 
-        initOps(width, height, scale, backgroundPixel, wlShmFormat, perfCountersEnabled);
+        initOps(width, height, backgroundPixel, wlShmFormat, perfCountersEnabled);
     }
 
     /**
@@ -85,7 +85,7 @@ public class WLSMSurfaceData extends SurfaceData implements WLSurfaceDataExt {
         SurfaceType surfaceType = graphicsConfig.getSurfaceType();
         Window target = peer.getTarget() instanceof Window ? (Window)peer.getTarget() : null;
         boolean perfCountersEnabled = target != null && AWTAccessor.getWindowAccessor().countersEnabled(target);
-        return new WLSMSurfaceData(peer, surfaceType, cm, graphicsConfig.getWlScale(), graphicsConfig.getWlShmFormat(), perfCountersEnabled);
+        return new WLSMSurfaceData(peer, surfaceType, cm, graphicsConfig.getWlShmFormat(), perfCountersEnabled);
     }
 
     @Override

src/java.desktop/unix/native/common/java2d/wl/WLBuffers.c

@@ -270,9 +270,6 @@ struct WLSurfaceBufferManager {
     /// Does not exceed MAX_BUFFERS_IN_USE elements.
     WLSurfaceBuffer *   buffersInUse;  // only accessed under showLock
 
-    /// The scale of wl_surface (see Wayland docs for more info on that).
-    jint                scale;         // only accessed under showLock
-
     pthread_mutex_t     drawLock;
 
     /**
@@ -760,7 +757,7 @@ SendShowBufferToWayland(WLSurfaceBufferManager * manager)
 
     // wl_buffer_listener will release bufferForShow when Wayland's done with it
     wl_surface_attach(manager->wlSurface, buffer->wlBuffer, 0, 0);
-    wl_surface_set_buffer_scale(manager->wlSurface, manager->scale);
+    //NB: do not specify scale for the buffer; we scale with wp_viewporter
 
     // Better wait for the frame event so as not to overwhelm Wayland with
     // frequent surface updates that it cannot deliver to the screen anyway.
@@ -935,7 +932,6 @@ HaveEnoughMemoryForWindow(jint width, jint height)
 WLSurfaceBufferManager *
 WLSBM_Create(jint width,
              jint height,
-             jint scale,
              jint bgPixel,
              jint wlShmFormat,
              jobject surfaceDataWeakRef,
@@ -955,7 +951,6 @@ WLSBM_Create(jint width,
 
     manager->bufferForDraw.width = width;
     manager->bufferForDraw.height = height;
-    manager->scale = scale;
     manager->bgPixel = bgPixel;
     manager->format = wlShmFormat;
     manager->surfaceDataWeakRef = surfaceDataWeakRef;
@@ -1116,7 +1111,7 @@ WLSB_DataGet(WLDrawBuffer * buffer)
 }
 
 void
-WLSBM_SizeChangeTo(WLSurfaceBufferManager * manager, jint width, jint height, jint scale)
+WLSBM_SizeChangeTo(WLSurfaceBufferManager * manager, jint width, jint height)
 {
     if (!HaveEnoughMemoryForWindow(width, height)) {
         JNU_ThrowOutOfMemoryError(getEnv(), "Wayland surface buffer too large");
@@ -1125,13 +1120,7 @@ WLSBM_SizeChangeTo(WLSurfaceBufferManager * manager, jint width, jint height, ji
 
     MUTEX_LOCK(manager->drawLock);
     MUTEX_LOCK(manager->showLock);
-    const bool change_needed =
-               manager->bufferForDraw.width != width
-            || manager->bufferForDraw.height != height
-            || manager->scale != scale;
-    manager->scale = scale;
-
-    if (change_needed) {
+    if (manager->bufferForDraw.width != width || manager->bufferForDraw.height != height) {
         manager->bufferForDraw.width  = width;
         manager->bufferForDraw.height = height;
         manager->bufferForDraw.resizePending = true;

src/java.desktop/unix/native/common/java2d/wl/WLBuffers.h

@@ -63,7 +63,7 @@ typedef void (*FrameCounterCallback)(jobject);
  * the drawing to displaying buffer, synchronization, and sending
  * the appropriate notifications to Wayland.
  */
-WLSurfaceBufferManager * WLSBM_Create(jint width, jint height, jint scale, jint bgPixel, jint wlShmFormat,
+WLSurfaceBufferManager * WLSBM_Create(jint width, jint height, jint bgPixel, jint wlShmFormat,
                                       jobject surfaceDataWeakRef,
                                       FrameCounterCallback frameSentCallback,
                                       FrameCounterCallback frameDroppedCallback);
@@ -113,7 +113,7 @@ jint WLSBM_HeightGet(WLSurfaceBufferManager *);
  * displays things will change later, but before the changes in drawing buffer
  * are propagated to the display buffer.
  */
-void WLSBM_SizeChangeTo(WLSurfaceBufferManager *, jint width, jint height, jint scale);
+void WLSBM_SizeChangeTo(WLSurfaceBufferManager *, jint width, jint height);
 
 /**
  * Returns a buffer managed by the WayLand Surface Buffer Manager

src/java.desktop/unix/native/common/java2d/wl/WLSMSurfaceData.c

@@ -130,7 +130,7 @@ Java_sun_java2d_wl_WLSMSurfaceData_revalidate(JNIEnv *env, jobject wsd,
         return;
     }
 
-    WLSBM_SizeChangeTo(wsdo->bufferManager, width, height, scale);
+    WLSBM_SizeChangeTo(wsdo->bufferManager, width, height);
 #endif /* !HEADLESS */
 }
 
@@ -364,7 +364,6 @@ JNIEXPORT void JNICALL
 Java_sun_java2d_wl_WLSMSurfaceData_initOps(JNIEnv *env, jobject wsd,
                                            jint width,
                                            jint height,
-                                           jint scale,
                                            jint backgroundRGB,
                                            jint wlShmFormat,
                                            jboolean perfCountersEnabled)
@@ -394,7 +393,7 @@ Java_sun_java2d_wl_WLSMSurfaceData_initOps(JNIEnv *env, jobject wsd,
     wsdo->sdOps.Unlock = WLSD_Unlock;
     wsdo->sdOps.GetRasInfo = WLSD_GetRasInfo;
     wsdo->sdOps.Dispose = WLSD_Dispose;
-    wsdo->bufferManager = WLSBM_Create(width, height, scale, backgroundRGB, wlShmFormat,
+    wsdo->bufferManager = WLSBM_Create(width, height, backgroundRGB, wlShmFormat,
                                        surfaceDataWeakRef,
                                        perfCountersEnabled ? CountFrameSent : NULL,
                                        perfCountersEnabled ? CountFrameDropped : NULL);

src/java.desktop/unix/native/libawt_wlawt/WLComponentPeer.c

@@ -90,6 +90,7 @@ static void delete_all_tokens(struct activation_token_list_item *list) {
 struct WLFrame {
     jobject nativeFramePeer; // weak reference
     struct wl_surface *wl_surface;
+    struct wp_viewport *wp_viewport;
     struct xdg_surface *xdg_surface;
     struct gtk_surface1 *gtk_surface;
     struct WLFrame *parent;
@@ -451,13 +452,14 @@ Java_sun_awt_wl_WLComponentPeer_nativeCreateWLSurface
     if (frame->wl_surface) return;
     frame->wl_surface = wl_compositor_create_surface(wl_compositor);
     CHECK_NULL(frame->wl_surface);
+    frame->wp_viewport = wp_viewporter_get_viewport(wp_viewporter, frame->wl_surface);
+    CHECK_NULL(frame->wp_viewport);
     frame->xdg_surface = xdg_wm_base_get_xdg_surface(xdg_wm_base, frame->wl_surface);
     CHECK_NULL(frame->xdg_surface);
     if (gtk_shell1 != NULL) {
         frame->gtk_surface = gtk_shell1_get_gtk_surface(gtk_shell1, frame->wl_surface);
         CHECK_NULL(frame->gtk_surface);
     }
-
     wl_surface_add_listener(frame->wl_surface, &wl_surface_listener, frame);
     xdg_surface_add_listener(frame->xdg_surface, &xdg_surface_listener, frame);
     frame->toplevel = JNI_TRUE;
@@ -530,6 +532,8 @@ Java_sun_awt_wl_WLComponentPeer_nativeCreateWLPopup
     if (frame->wl_surface) return;
     frame->wl_surface = wl_compositor_create_surface(wl_compositor);
     CHECK_NULL(frame->wl_surface);
+    frame->wp_viewport = wp_viewporter_get_viewport(wp_viewporter, frame->wl_surface);
+    CHECK_NULL(frame->wp_viewport);
     frame->xdg_surface = xdg_wm_base_get_xdg_surface(xdg_wm_base, frame->wl_surface);
     CHECK_NULL(frame->xdg_surface);
 
@@ -544,7 +548,6 @@ Java_sun_awt_wl_WLComponentPeer_nativeCreateWLPopup
     CHECK_NULL(frame->xdg_popup);
     xdg_popup_add_listener(frame->xdg_popup, &xdg_popup_listener, frame);
     xdg_positioner_destroy(xdg_positioner);
-
     // From xdg-shell.xml: "After creating a role-specific object and
     // setting it up, the client must perform an initial commit
     // without any buffer attached"
@@ -586,6 +589,7 @@ DoHide(JNIEnv *env, struct WLFrame *frame)
         if (frame->gtk_surface != NULL) {
             gtk_surface1_destroy(frame->gtk_surface);
         }
+        wp_viewport_destroy(frame->wp_viewport);
         xdg_surface_destroy(frame->xdg_surface);
         wl_surface_destroy(frame->wl_surface);
         delete_all_tokens(frame->activation_token_list);
@@ -596,6 +600,7 @@ DoHide(JNIEnv *env, struct WLFrame *frame)
         frame->xdg_surface = NULL;
         frame->xdg_toplevel = NULL;
         frame->xdg_popup = NULL;
+        frame->wp_viewport = NULL;
         frame->toplevel = JNI_FALSE;
     }
 }
@@ -644,6 +649,21 @@ JNIEXPORT void JNICALL Java_sun_awt_wl_WLComponentPeer_nativeStartResize
     }
 }
 
+/**
+ * Specifies the size of the Wayland's surface in surface units.
+ * For the resulting image on the screen to look sharp this size should be
+ * multiple of backing buffer's size with the ratio matching the display scale.
+ */
+JNIEXPORT void JNICALL Java_sun_awt_wl_WLComponentPeer_nativeSetSurfaceSize
+        (JNIEnv *env, jobject obj, jlong ptr, jint width, jint height)
+{
+    struct WLFrame *frame = jlong_to_ptr(ptr);
+    if (frame->wp_viewport != NULL) {
+        wp_viewport_set_destination(frame->wp_viewport, width, height);
+    }
+}
+
+
 JNIEXPORT void JNICALL Java_sun_awt_wl_WLComponentPeer_nativeSetWindowGeometry
         (JNIEnv *env, jobject obj, jlong ptr, jint x, jint y, jint width, jint height)
 {

src/java.desktop/unix/native/libawt_wlawt/WLToolkit.c

@@ -64,6 +64,7 @@ struct wl_display *wl_display = NULL;
 struct wl_shm *wl_shm = NULL;
 struct wl_compositor *wl_compositor = NULL;
 struct xdg_wm_base *xdg_wm_base = NULL;
+struct wp_viewporter *wp_viewporter = NULL;
 struct xdg_activation_v1 *xdg_activation_v1 = NULL;
 struct gtk_shell1* gtk_shell1 = NULL;
 struct wl_seat     *wl_seat = NULL;
@@ -524,6 +525,8 @@ registry_global(void *data, struct wl_registry *wl_registry,
       wl_ddm = wl_registry_bind(wl_registry, name,&wl_data_device_manager_interface, 3);
     } else if (strcmp(interface, zwp_primary_selection_device_manager_v1_interface.name) == 0) {
         zwp_selection_dm = wl_registry_bind(wl_registry, name, &zwp_primary_selection_device_manager_v1_interface, 1);
+    } else if (strcmp(interface, wp_viewporter_interface.name) == 0) {
+        wp_viewporter = wl_registry_bind(wl_registry, name, &wp_viewporter_interface, 1);
     }
 
 #ifdef WAKEFIELD_ROBOT

src/java.desktop/unix/native/libawt_wlawt/WLToolkit.h

@@ -28,6 +28,7 @@
 #include "xdg-shell-client-protocol.h"
 #include "xdg-activation-v1-client-protocol.h"
 #include "primary-selection-client-protocol.h"
+#include "viewporter-client-protocol.h"
 #include "jvm_md.h"
 #include "jni_util.h"
 
@@ -54,6 +55,7 @@ extern struct wl_display *wl_display;
 extern struct wl_pointer *wl_pointer;
 extern struct wl_compositor *wl_compositor;
 extern struct xdg_wm_base *xdg_wm_base;
+extern struct wp_viewporter *wp_viewporter;
 extern struct xdg_activation_v1 *xdg_activation_v1;
 extern struct gtk_shell1* gtk_shell1; // optional, check for NULL before use
 

src/java.desktop/unix/native/libawt_wlawt/viewporter-client-protocol.c

@@ -0,0 +1,74 @@
+/* Generated by wayland-scanner 1.19.0 */
+
+/*
+ * Copyright © 2013-2016 Collabora, Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <stdlib.h>
+#include <stdint.h>
+#include "wayland-util.h"
+
+#ifndef __has_attribute
+# define __has_attribute(x) 0  /* Compatibility with non-clang compilers. */
+#endif
+
+#if (__has_attribute(visibility) || defined(__GNUC__) && __GNUC__ >= 4)
+#define WL_PRIVATE __attribute__ ((visibility("hidden")))
+#else
+#define WL_PRIVATE
+#endif
+
+extern const struct wl_interface wl_surface_interface;
+extern const struct wl_interface wp_viewport_interface;
+
+static const struct wl_interface *viewporter_types[] = {
+	NULL,
+	NULL,
+	NULL,
+	NULL,
+	&wp_viewport_interface,
+	&wl_surface_interface,
+};
+
+static const struct wl_message wp_viewporter_requests[] = {
+	{ "destroy", "", viewporter_types + 0 },
+	{ "get_viewport", "no", viewporter_types + 4 },
+};
+
+WL_PRIVATE const struct wl_interface wp_viewporter_interface = {
+	"wp_viewporter", 1,
+	2, wp_viewporter_requests,
+	0, NULL,
+};
+
+static const struct wl_message wp_viewport_requests[] = {
+	{ "destroy", "", viewporter_types + 0 },
+	{ "set_source", "ffff", viewporter_types + 0 },
+	{ "set_destination", "ii", viewporter_types + 0 },
+};
+
+WL_PRIVATE const struct wl_interface wp_viewport_interface = {
+	"wp_viewport", 1,
+	3, wp_viewport_requests,
+	0, NULL,
+};
+

src/java.desktop/unix/native/libawt_wlawt/viewporter-client-protocol.h

@@ -0,0 +1,402 @@
+/* Generated by wayland-scanner 1.19.0 */
+
+#ifndef VIEWPORTER_CLIENT_PROTOCOL_H
+#define VIEWPORTER_CLIENT_PROTOCOL_H
+
+#include <stdint.h>
+#include <stddef.h>
+#include "wayland-client.h"
+
+#ifdef  __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @page page_viewporter The viewporter protocol
+ * @section page_ifaces_viewporter Interfaces
+ * - @subpage page_iface_wp_viewporter - surface cropping and scaling
+ * - @subpage page_iface_wp_viewport - crop and scale interface to a wl_surface
+ * @section page_copyright_viewporter Copyright
+ * <pre>
+ *
+ * Copyright © 2013-2016 Collabora, Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ * </pre>
+ */
+struct wl_surface;
+struct wp_viewport;
+struct wp_viewporter;
+
+#ifndef WP_VIEWPORTER_INTERFACE
+#define WP_VIEWPORTER_INTERFACE
+/**
+ * @page page_iface_wp_viewporter wp_viewporter
+ * @section page_iface_wp_viewporter_desc Description
+ *
+ * The global interface exposing surface cropping and scaling
+ * capabilities is used to instantiate an interface extension for a
+ * wl_surface object. This extended interface will then allow
+ * cropping and scaling the surface contents, effectively
+ * disconnecting the direct relationship between the buffer and the
+ * surface size.
+ * @section page_iface_wp_viewporter_api API
+ * See @ref iface_wp_viewporter.
+ */
+/**
+ * @defgroup iface_wp_viewporter The wp_viewporter interface
+ *
+ * The global interface exposing surface cropping and scaling
+ * capabilities is used to instantiate an interface extension for a
+ * wl_surface object. This extended interface will then allow
+ * cropping and scaling the surface contents, effectively
+ * disconnecting the direct relationship between the buffer and the
+ * surface size.
+ */
+extern const struct wl_interface wp_viewporter_interface;
+#endif
+#ifndef WP_VIEWPORT_INTERFACE
+#define WP_VIEWPORT_INTERFACE
+/**
+ * @page page_iface_wp_viewport wp_viewport
+ * @section page_iface_wp_viewport_desc Description
+ *
+ * An additional interface to a wl_surface object, which allows the
+ * client to specify the cropping and scaling of the surface
+ * contents.
+ *
+ * This interface works with two concepts: the source rectangle (src_x,
+ * src_y, src_width, src_height), and the destination size (dst_width,
+ * dst_height). The contents of the source rectangle are scaled to the
+ * destination size, and content outside the source rectangle is ignored.
+ * This state is double-buffered, and is applied on the next
+ * wl_surface.commit.
+ *
+ * The two parts of crop and scale state are independent: the source
+ * rectangle, and the destination size. Initially both are unset, that
+ * is, no scaling is applied. The whole of the current wl_buffer is
+ * used as the source, and the surface size is as defined in
+ * wl_surface.attach.
+ *
+ * If the destination size is set, it causes the surface size to become
+ * dst_width, dst_height. The source (rectangle) is scaled to exactly
+ * this size. This overrides whatever the attached wl_buffer size is,
+ * unless the wl_buffer is NULL. If the wl_buffer is NULL, the surface
+ * has no content and therefore no size. Otherwise, the size is always
+ * at least 1x1 in surface local coordinates.
+ *
+ * If the source rectangle is set, it defines what area of the wl_buffer is
+ * taken as the source. If the source rectangle is set and the destination
+ * size is not set, then src_width and src_height must be integers, and the
+ * surface size becomes the source rectangle size. This results in cropping
+ * without scaling. If src_width or src_height are not integers and
+ * destination size is not set, the bad_size protocol error is raised when
+ * the surface state is applied.
+ *
+ * The coordinate transformations from buffer pixel coordinates up to
+ * the surface-local coordinates happen in the following order:
+ * 1. buffer_transform (wl_surface.set_buffer_transform)
+ * 2. buffer_scale (wl_surface.set_buffer_scale)
+ * 3. crop and scale (wp_viewport.set*)
+ * This means, that the source rectangle coordinates of crop and scale
+ * are given in the coordinates after the buffer transform and scale,
+ * i.e. in the coordinates that would be the surface-local coordinates
+ * if the crop and scale was not applied.
+ *
+ * If src_x or src_y are negative, the bad_value protocol error is raised.
+ * Otherwise, if the source rectangle is partially or completely outside of
+ * the non-NULL wl_buffer, then the out_of_buffer protocol error is raised
+ * when the surface state is applied. A NULL wl_buffer does not raise the
+ * out_of_buffer error.
+ *
+ * If the wl_surface associated with the wp_viewport is destroyed,
+ * all wp_viewport requests except 'destroy' raise the protocol error
+ * no_surface.
+ *
+ * If the wp_viewport object is destroyed, the crop and scale
+ * state is removed from the wl_surface. The change will be applied
+ * on the next wl_surface.commit.
+ * @section page_iface_wp_viewport_api API
+ * See @ref iface_wp_viewport.
+ */
+/**
+ * @defgroup iface_wp_viewport The wp_viewport interface
+ *
+ * An additional interface to a wl_surface object, which allows the
+ * client to specify the cropping and scaling of the surface
+ * contents.
+ *
+ * This interface works with two concepts: the source rectangle (src_x,
+ * src_y, src_width, src_height), and the destination size (dst_width,
+ * dst_height). The contents of the source rectangle are scaled to the
+ * destination size, and content outside the source rectangle is ignored.
+ * This state is double-buffered, and is applied on the next
+ * wl_surface.commit.
+ *
+ * The two parts of crop and scale state are independent: the source
+ * rectangle, and the destination size. Initially both are unset, that
+ * is, no scaling is applied. The whole of the current wl_buffer is
+ * used as the source, and the surface size is as defined in
+ * wl_surface.attach.
+ *
+ * If the destination size is set, it causes the surface size to become
+ * dst_width, dst_height. The source (rectangle) is scaled to exactly
+ * this size. This overrides whatever the attached wl_buffer size is,
+ * unless the wl_buffer is NULL. If the wl_buffer is NULL, the surface
+ * has no content and therefore no size. Otherwise, the size is always
+ * at least 1x1 in surface local coordinates.
+ *
+ * If the source rectangle is set, it defines what area of the wl_buffer is
+ * taken as the source. If the source rectangle is set and the destination
+ * size is not set, then src_width and src_height must be integers, and the
+ * surface size becomes the source rectangle size. This results in cropping
+ * without scaling. If src_width or src_height are not integers and
+ * destination size is not set, the bad_size protocol error is raised when
+ * the surface state is applied.
+ *
+ * The coordinate transformations from buffer pixel coordinates up to
+ * the surface-local coordinates happen in the following order:
+ * 1. buffer_transform (wl_surface.set_buffer_transform)
+ * 2. buffer_scale (wl_surface.set_buffer_scale)
+ * 3. crop and scale (wp_viewport.set*)
+ * This means, that the source rectangle coordinates of crop and scale
+ * are given in the coordinates after the buffer transform and scale,
+ * i.e. in the coordinates that would be the surface-local coordinates
+ * if the crop and scale was not applied.
+ *
+ * If src_x or src_y are negative, the bad_value protocol error is raised.
+ * Otherwise, if the source rectangle is partially or completely outside of
+ * the non-NULL wl_buffer, then the out_of_buffer protocol error is raised
+ * when the surface state is applied. A NULL wl_buffer does not raise the
+ * out_of_buffer error.
+ *
+ * If the wl_surface associated with the wp_viewport is destroyed,
+ * all wp_viewport requests except 'destroy' raise the protocol error
+ * no_surface.
+ *
+ * If the wp_viewport object is destroyed, the crop and scale
+ * state is removed from the wl_surface. The change will be applied
+ * on the next wl_surface.commit.
+ */
+extern const struct wl_interface wp_viewport_interface;
+#endif
+
+#ifndef WP_VIEWPORTER_ERROR_ENUM
+#define WP_VIEWPORTER_ERROR_ENUM
+enum wp_viewporter_error {
+	/**
+	 * the surface already has a viewport object associated
+	 */
+	WP_VIEWPORTER_ERROR_VIEWPORT_EXISTS = 0,
+};
+#endif /* WP_VIEWPORTER_ERROR_ENUM */
+
+#define WP_VIEWPORTER_DESTROY 0
+#define WP_VIEWPORTER_GET_VIEWPORT 1
+
+
+/**
+ * @ingroup iface_wp_viewporter
+ */
+#define WP_VIEWPORTER_DESTROY_SINCE_VERSION 1
+/**
+ * @ingroup iface_wp_viewporter
+ */
+#define WP_VIEWPORTER_GET_VIEWPORT_SINCE_VERSION 1
+
+/** @ingroup iface_wp_viewporter */
+static inline void
+wp_viewporter_set_user_data(struct wp_viewporter *wp_viewporter, void *user_data)
+{
+	wl_proxy_set_user_data((struct wl_proxy *) wp_viewporter, user_data);
+}
+
+/** @ingroup iface_wp_viewporter */
+static inline void *
+wp_viewporter_get_user_data(struct wp_viewporter *wp_viewporter)
+{
+	return wl_proxy_get_user_data((struct wl_proxy *) wp_viewporter);
+}
+
+static inline uint32_t
+wp_viewporter_get_version(struct wp_viewporter *wp_viewporter)
+{
+	return wl_proxy_get_version((struct wl_proxy *) wp_viewporter);
+}
+
+/**
+ * @ingroup iface_wp_viewporter
+ *
+ * Informs the server that the client will not be using this
+ * protocol object anymore. This does not affect any other objects,
+ * wp_viewport objects included.
+ */
+static inline void
+wp_viewporter_destroy(struct wp_viewporter *wp_viewporter)
+{
+	wl_proxy_marshal((struct wl_proxy *) wp_viewporter,
+			 WP_VIEWPORTER_DESTROY);
+
+	wl_proxy_destroy((struct wl_proxy *) wp_viewporter);
+}
+
+/**
+ * @ingroup iface_wp_viewporter
+ *
+ * Instantiate an interface extension for the given wl_surface to
+ * crop and scale its content. If the given wl_surface already has
+ * a wp_viewport object associated, the viewport_exists
+ * protocol error is raised.
+ */
+static inline struct wp_viewport *
+wp_viewporter_get_viewport(struct wp_viewporter *wp_viewporter, struct wl_surface *surface)
+{
+	struct wl_proxy *id;
+
+	id = wl_proxy_marshal_constructor((struct wl_proxy *) wp_viewporter,
+			 WP_VIEWPORTER_GET_VIEWPORT, &wp_viewport_interface, NULL, surface);
+
+	return (struct wp_viewport *) id;
+}
+
+#ifndef WP_VIEWPORT_ERROR_ENUM
+#define WP_VIEWPORT_ERROR_ENUM
+enum wp_viewport_error {
+	/**
+	 * negative or zero values in width or height
+	 */
+	WP_VIEWPORT_ERROR_BAD_VALUE = 0,
+	/**
+	 * destination size is not integer
+	 */
+	WP_VIEWPORT_ERROR_BAD_SIZE = 1,
+	/**
+	 * source rectangle extends outside of the content area
+	 */
+	WP_VIEWPORT_ERROR_OUT_OF_BUFFER = 2,
+	/**
+	 * the wl_surface was destroyed
+	 */
+	WP_VIEWPORT_ERROR_NO_SURFACE = 3,
+};
+#endif /* WP_VIEWPORT_ERROR_ENUM */
+
+#define WP_VIEWPORT_DESTROY 0
+#define WP_VIEWPORT_SET_SOURCE 1
+#define WP_VIEWPORT_SET_DESTINATION 2
+
+
+/**
+ * @ingroup iface_wp_viewport
+ */
+#define WP_VIEWPORT_DESTROY_SINCE_VERSION 1
+/**
+ * @ingroup iface_wp_viewport
+ */
+#define WP_VIEWPORT_SET_SOURCE_SINCE_VERSION 1
+/**
+ * @ingroup iface_wp_viewport
+ */
+#define WP_VIEWPORT_SET_DESTINATION_SINCE_VERSION 1
+
+/** @ingroup iface_wp_viewport */
+static inline void
+wp_viewport_set_user_data(struct wp_viewport *wp_viewport, void *user_data)
+{
+	wl_proxy_set_user_data((struct wl_proxy *) wp_viewport, user_data);
+}
+
+/** @ingroup iface_wp_viewport */
+static inline void *
+wp_viewport_get_user_data(struct wp_viewport *wp_viewport)
+{
+	return wl_proxy_get_user_data((struct wl_proxy *) wp_viewport);
+}
+
+static inline uint32_t
+wp_viewport_get_version(struct wp_viewport *wp_viewport)
+{
+	return wl_proxy_get_version((struct wl_proxy *) wp_viewport);
+}
+
+/**
+ * @ingroup iface_wp_viewport
+ *
+ * The associated wl_surface's crop and scale state is removed.
+ * The change is applied on the next wl_surface.commit.
+ */
+static inline void
+wp_viewport_destroy(struct wp_viewport *wp_viewport)
+{
+	wl_proxy_marshal((struct wl_proxy *) wp_viewport,
+			 WP_VIEWPORT_DESTROY);
+
+	wl_proxy_destroy((struct wl_proxy *) wp_viewport);
+}
+
+/**
+ * @ingroup iface_wp_viewport
+ *
+ * Set the source rectangle of the associated wl_surface. See
+ * wp_viewport for the description, and relation to the wl_buffer
+ * size.
+ *
+ * If all of x, y, width and height are -1.0, the source rectangle is
+ * unset instead. Any other set of values where width or height are zero
+ * or negative, or x or y are negative, raise the bad_value protocol
+ * error.
+ *
+ * The crop and scale state is double-buffered state, and will be
+ * applied on the next wl_surface.commit.
+ */
+static inline void
+wp_viewport_set_source(struct wp_viewport *wp_viewport, wl_fixed_t x, wl_fixed_t y, wl_fixed_t width, wl_fixed_t height)
+{
+	wl_proxy_marshal((struct wl_proxy *) wp_viewport,
+			 WP_VIEWPORT_SET_SOURCE, x, y, width, height);
+}
+
+/**
+ * @ingroup iface_wp_viewport
+ *
+ * Set the destination size of the associated wl_surface. See
+ * wp_viewport for the description, and relation to the wl_buffer
+ * size.
+ *
+ * If width is -1 and height is -1, the destination size is unset
+ * instead. Any other pair of values for width and height that
+ * contains zero or negative values raises the bad_value protocol
+ * error.
+ *
+ * The crop and scale state is double-buffered state, and will be
+ * applied on the next wl_surface.commit.
+ */
+static inline void
+wp_viewport_set_destination(struct wp_viewport *wp_viewport, int32_t width, int32_t height)
+{
+	wl_proxy_marshal((struct wl_proxy *) wp_viewport,
+			 WP_VIEWPORT_SET_DESTINATION, width, height);
+}
+
+#ifdef  __cplusplus
+}
+#endif
+
+#endif