Support fractional-scale-v1

This make text less blurry. It continues to works without.

before:
https://dav.missbanal.net/00bd0fd5-e22f-4a60-87f8-ce6f400d33c9.png

after:
https://dav.missbanal.net/a3f02f1e-d6ce-4378-a141-e2093ba87eed.png
Signed-off-by: Willow Barraco <contact@willowbarraco.fr>
Signed-off-by: Maarten van Gompel <proycon@anaproy.nl>

drw.c

@@ -6,7 +6,7 @@
 #include "shm_open.h"
 
 void
-drwsurf_resize(struct drwsurf *ds, uint32_t w, uint32_t h, uint32_t s) {
+drwsurf_resize(struct drwsurf *ds, uint32_t w, uint32_t h, double s) {
 	if (ds->buf) {
 		munmap(ds->pool_data, ds->size);
 		wl_buffer_destroy(ds->buf);
@@ -131,7 +131,5 @@ setup_buffer(struct drwsurf *drwsurf) {
 	pango_layout_set_auto_dir(drwsurf->layout, false);
 	cairo_save(drwsurf->cairo);
 
-	wl_surface_set_buffer_scale(drwsurf->surf, drwsurf->scale);
-
 	return 0;
 }

drw.h

@@ -9,7 +9,8 @@ struct drw {
 	PangoFontDescription *font_description;
 };
 struct drwsurf {
-	uint32_t width, height, scale, size;
+	uint32_t width, height, size;
+	double scale;
 
 	struct drw *ctx;
 	struct wl_surface *surf;
@@ -22,7 +23,7 @@ struct drwsurf {
 };
 struct kbd;
 
-void drwsurf_resize(struct drwsurf *ds, uint32_t w, uint32_t h, uint32_t s);
+void drwsurf_resize(struct drwsurf *ds, uint32_t w, uint32_t h, double s);
 void drwsurf_flip(struct drwsurf *ds);
 
 typedef union {

keyboard.c

@@ -580,7 +580,7 @@ kbd_draw_layout(struct kbd *kb) {
 
 void
 kbd_resize(struct kbd *kb, struct layout *layouts, uint8_t layoutcount) {
-	fprintf(stderr, "Resize %dx%d %d, %d layouts\n", kb->w, kb->h, kb->scale,
+	fprintf(stderr, "Resize %dx%d %f, %d layouts\n", kb->w, kb->h, kb->scale,
 	        layoutcount);
 
 	drwsurf_resize(kb->surf, kb->w, kb->h, kb->scale);

keyboard.h

@@ -95,7 +95,8 @@ struct kbd {
 
 	bool print;
 	bool print_intersect;
-	uint32_t w, h, scale;
+	uint32_t w, h;
+	double scale;
 	bool landscape;
 	uint8_t mods;
 	uint8_t compose;

main.c

@@ -1,6 +1,8 @@
 #include "proto/virtual-keyboard-unstable-v1-client-protocol.h"
 #include "proto/wlr-layer-shell-unstable-v1-client-protocol.h"
 #include "proto/xdg-shell-client-protocol.h"
+#include "proto/fractional-scale-v1-client-protocol.h"
+#include "proto/viewporter-client-protocol.h"
 #include <linux/input-event-codes.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -36,6 +38,10 @@ static struct xdg_surface *popup_xdg_surface;
 static struct xdg_popup *popup_xdg_popup;
 static struct xdg_positioner *popup_xdg_positioner;
 static struct zwp_virtual_keyboard_manager_v1 *vkbd_mgr;
+static struct wp_fractional_scale_v1 *wfs_draw_surf;
+static struct wp_fractional_scale_manager_v1 *wfs_mgr;
+static struct wp_viewport *draw_surf_viewport, *popup_draw_surf_viewport;
+static struct wp_viewporter *viewporter;
 
 struct Output {
     uint32_t name;
@@ -355,7 +361,11 @@ display_handle_done(void *data, struct wl_output *wl_output) {}
 static void
 display_handle_scale(void *data, struct wl_output *wl_output, int32_t scale) {
 	((struct Output*)data)->scale = scale;
+	if (wfs_mgr && viewporter) {
+		return;
+	}
 	keyboard.scale = scale;
+	wl_surface_set_buffer_scale(draw_surf.surf, scale);
 }
 
 static void
@@ -404,6 +414,12 @@ handle_global(void *data, struct wl_registry *registry, uint32_t name,
 		wm_base =
 		  wl_registry_bind(registry, name, &xdg_wm_base_interface, 1);
 		xdg_wm_base_add_listener(wm_base, &xdg_wm_base_listener, NULL);
+	} else if (strcmp(interface, wp_fractional_scale_manager_v1_interface.name) == 0) {
+		wfs_mgr =
+		  wl_registry_bind(registry, name, &wp_fractional_scale_manager_v1_interface, 1);
+	} else if (strcmp(interface, wp_viewporter_interface.name) == 0) {
+		viewporter =
+		  wl_registry_bind(registry, name, &wp_viewporter_interface, 1);
 	} else if (strcmp(interface,
 	                  zwp_virtual_keyboard_manager_v1_interface.name) == 0) {
 		vkbd_mgr = wl_registry_bind(registry, name,
@@ -458,6 +474,18 @@ static const struct xdg_popup_listener xdg_popup_listener = {
 	.popup_done = xdg_popup_done,
 };
 
+static void
+wp_fractional_scale_prefered_scale(void *data,
+	struct wp_fractional_scale_v1 *wp_fractional_scale_v1,
+	uint32_t scale)
+{
+	keyboard.scale = (double)scale / 120;
+}
+
+static const struct wp_fractional_scale_v1_listener wp_fractional_scale_listener = {
+	.preferred_scale = wp_fractional_scale_prefered_scale,
+};
+
 void
 layer_surface_configure(void *data, struct zwlr_layer_surface_v1 *surface,
                         uint32_t serial, uint32_t w, uint32_t h) {
@@ -465,20 +493,48 @@ layer_surface_configure(void *data, struct zwlr_layer_surface_v1 *surface,
 		keyboard.w = w;
 		keyboard.h = h;
 
-		xdg_positioner_set_size(popup_xdg_positioner, w, h*2);
+		if (wfs_mgr && viewporter) {
-		xdg_positioner_set_anchor_rect(popup_xdg_positioner, 0, -h, w, h*2);
+			if (!wfs_draw_surf) {
+				wfs_draw_surf = wp_fractional_scale_manager_v1_get_fractional_scale(wfs_mgr, draw_surf.surf);
+				wp_fractional_scale_v1_add_listener(wfs_draw_surf, &wp_fractional_scale_listener, NULL);
+			}
+			if (!draw_surf_viewport) {
+				draw_surf_viewport = wp_viewporter_get_viewport(viewporter, draw_surf.surf);
+			}
+			wp_viewport_set_destination(draw_surf_viewport, keyboard.w, keyboard.h);
+		} else {
+			wl_surface_set_buffer_scale(draw_surf.surf, keyboard.scale);
+		}
 
 		if (popup_xdg_popup) {
 			xdg_popup_destroy(popup_xdg_popup);
 		}
+		if (popup_xdg_surface) {
+			xdg_surface_destroy(popup_xdg_surface);
+		}
+		if (popup_draw_surf.surf) {
+			wl_surface_destroy(popup_draw_surf.surf);
+		}
 
 		popup_draw_surf.surf = wl_compositor_create_surface(compositor);
+
+		xdg_positioner_set_size(popup_xdg_positioner, w, h*2);
+		xdg_positioner_set_anchor_rect(popup_xdg_positioner, 0, -h, w, h*2);
+
 		wl_surface_set_input_region(popup_draw_surf.surf, empty_region);
 		popup_xdg_surface = xdg_wm_base_get_xdg_surface(wm_base, popup_draw_surf.surf);
 		xdg_surface_add_listener(popup_xdg_surface, &xdg_popup_surface_listener, NULL);
 		popup_xdg_popup = xdg_surface_get_popup(popup_xdg_surface, NULL, popup_xdg_positioner);
 		xdg_popup_add_listener(popup_xdg_popup, &xdg_popup_listener, NULL);
 		zwlr_layer_surface_v1_get_popup(layer_surface, popup_xdg_popup);
+
+		if (wfs_mgr && viewporter) {
+			popup_draw_surf_viewport = wp_viewporter_get_viewport(viewporter, popup_draw_surf.surf);
+			wp_viewport_set_destination(popup_draw_surf_viewport, keyboard.w, keyboard.h * 2);
+		} else {
+			wl_surface_set_buffer_scale(popup_draw_surf.surf, keyboard.scale);
+		}
+
 		wl_surface_commit(popup_draw_surf.surf);
 	}
 

proto/fractional-scale-v1.xml

@@ -0,0 +1,102 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<protocol name="fractional_scale_v1">
+  <copyright>
+    Copyright © 2022 Kenny Levinsen
+
+    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.
+  </copyright>
+
+  <description summary="Protocol for requesting fractional surface scales">
+    This protocol allows a compositor to suggest for surfaces to render at
+    fractional scales.
+
+    A client can submit scaled content by utilizing wp_viewport. This is done by
+    creating a wp_viewport object for the surface and setting the destination
+    rectangle to the surface size before the scale factor is applied.
+
+    The buffer size is calculated by multiplying the surface size by the
+    intended scale.
+
+    The wl_surface buffer scale should remain set to 1.
+
+    If a surface has a surface-local size of 100 px by 50 px and wishes to
+    submit buffers with a scale of 1.5, then a buffer of 150px by 75 px should
+    be used and the wp_viewport destination rectangle should be 100 px by 50 px.
+
+    For toplevel surfaces, the size is rounded halfway away from zero. The
+    rounding algorithm for subsurface position and size is not defined.
+  </description>
+
+  <interface name="wp_fractional_scale_manager_v1" version="1">
+    <description summary="fractional surface scale information">
+      A global interface for requesting surfaces to use fractional scales.
+    </description>
+
+    <request name="destroy" type="destructor">
+      <description summary="unbind the fractional surface scale interface">
+        Informs the server that the client will not be using this protocol
+        object anymore. This does not affect any other objects,
+        wp_fractional_scale_v1 objects included.
+      </description>
+    </request>
+
+    <enum name="error">
+      <entry name="fractional_scale_exists" value="0"
+        summary="the surface already has a fractional_scale object associated"/>
+    </enum>
+
+    <request name="get_fractional_scale">
+      <description summary="extend surface interface for scale information">
+        Create an add-on object for the the wl_surface to let the compositor
+        request fractional scales. If the given wl_surface already has a
+        wp_fractional_scale_v1 object associated, the fractional_scale_exists
+        protocol error is raised.
+      </description>
+      <arg name="id" type="new_id" interface="wp_fractional_scale_v1"
+           summary="the new surface scale info interface id"/>
+      <arg name="surface" type="object" interface="wl_surface"
+           summary="the surface"/>
+    </request>
+  </interface>
+
+  <interface name="wp_fractional_scale_v1" version="1">
+    <description summary="fractional scale interface to a wl_surface">
+      An additional interface to a wl_surface object which allows the compositor
+      to inform the client of the preferred scale.
+    </description>
+
+    <request name="destroy" type="destructor">
+      <description summary="remove surface scale information for surface">
+        Destroy the fractional scale object. When this object is destroyed,
+        preferred_scale events will no longer be sent.
+      </description>
+    </request>
+
+    <event name="preferred_scale">
+      <description summary="notify of new preferred scale">
+        Notification of a new preferred scale for this surface that the
+        compositor suggests that the client should use.
+
+        The sent scale is the numerator of a fraction with a denominator of 120.
+      </description>
+      <arg name="scale" type="uint" summary="the new preferred scale"/>
+    </event>
+  </interface>
+</protocol>

proto/viewporter.xml

@@ -0,0 +1,180 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<protocol name="viewporter">
+
+  <copyright>
+    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.
+  </copyright>
+
+  <interface name="wp_viewporter" version="1">
+    <description summary="surface cropping and scaling">
+      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.
+    </description>
+
+    <request name="destroy" type="destructor">
+      <description summary="unbind from the cropping and scaling interface">
+	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.
+      </description>
+    </request>
+
+    <enum name="error">
+      <entry name="viewport_exists" value="0"
+             summary="the surface already has a viewport object associated"/>
+    </enum>
+
+    <request name="get_viewport">
+      <description summary="extend surface interface for crop and scale">
+	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.
+      </description>
+      <arg name="id" type="new_id" interface="wp_viewport"
+           summary="the new viewport interface id"/>
+      <arg name="surface" type="object" interface="wl_surface"
+           summary="the surface"/>
+    </request>
+  </interface>
+
+  <interface name="wp_viewport" version="1">
+    <description summary="crop and scale interface to a wl_surface">
+      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.
+    </description>
+
+    <request name="destroy" type="destructor">
+      <description summary="remove scaling and cropping from the surface">
+	The associated wl_surface's crop and scale state is removed.
+	The change is applied on the next wl_surface.commit.
+      </description>
+    </request>
+
+    <enum name="error">
+      <entry name="bad_value" value="0"
+	     summary="negative or zero values in width or height"/>
+      <entry name="bad_size" value="1"
+	     summary="destination size is not integer"/>
+      <entry name="out_of_buffer" value="2"
+	     summary="source rectangle extends outside of the content area"/>
+      <entry name="no_surface" value="3"
+	     summary="the wl_surface was destroyed"/>
+    </enum>
+
+    <request name="set_source">
+      <description summary="set the source rectangle for cropping">
+	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.
+      </description>
+      <arg name="x" type="fixed" summary="source rectangle x"/>
+      <arg name="y" type="fixed" summary="source rectangle y"/>
+      <arg name="width" type="fixed" summary="source rectangle width"/>
+      <arg name="height" type="fixed" summary="source rectangle height"/>
+    </request>
+
+    <request name="set_destination">
+      <description summary="set the surface size for scaling">
+	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.
+      </description>
+      <arg name="width" type="int" summary="surface width"/>
+      <arg name="height" type="int" summary="surface height"/>
+    </request>
+  </interface>
+
+</protocol>