[snapshot][SDL] Display headless mode and snapshots (#17917)

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

tests/components/sdl/common.yaml

@@ -14,6 +14,15 @@ display:
       position:
         x: 100
         y: 100
+    snapshot_key: SDLK_F12
+
+  - platform: sdl
+    id: headless_display
+    headless: true
+    show_test_card: true
+    dimensions:
+      width: 320
+      height: 240
 
   - platform: sdl
     id: second_display
@@ -46,3 +55,21 @@ binary_sensor:
     sdl_id: sdl_sdl_display
     id: key_enter
     key: SDLK_RETURN
+
+esphome:
+  # A name of your own is only good for one snapshot - a second one under the same name fails
+  # rather than writing over the first - so these run once rather than on a repeating interval.
+  on_boot:
+    - delay: 2s
+    - snapshot.take:
+        id: headless_display
+        filename: test_card.bmp
+    - snapshot.take:
+        id: headless_display
+        filename: !lambda 'return "shot.bmp";'
+
+interval:
+  # A generated name has the time in it, so this one can repeat.
+  - interval: 10s
+    then:
+      - snapshot.take: sdl_sdl_display

tests/components/sdl/validate.host.yaml

@@ -0,0 +1,29 @@
+# Config-only test for the headless and screenshot options. The combinations that must be
+# rejected are covered by tests/component_tests/sdl/test_sdl.py; this file checks that the
+# accepted forms validate together.
+host:
+  mac_address: "62:23:45:AF:B3:DD"
+
+display:
+  - platform: sdl
+    id: headless_display
+    headless: true
+    dimensions: 320x240
+
+  - platform: sdl
+    id: windowed_display
+    dimensions: 320x240
+    snapshot_key: SDLK_F12
+
+binary_sensor:
+  - platform: sdl
+    sdl_id: windowed_display
+    id: key_up
+    key: SDLK_UP
+
+interval:
+  - interval: 10s
+    then:
+      - snapshot.take:
+          id: headless_display
+          filename: periodic.bmp

tests/components/snapshot/common.yaml

@@ -0,0 +1,34 @@
+display:
+  - platform: snapshot
+    id: snapshot_display
+    update_interval: 1s
+    show_test_card: true
+    # An odd width exercises the row padding in the BMP writer
+    dimensions:
+      width: 101
+      height: 64
+
+  - platform: snapshot
+    id: snapshot_rotated
+    rotation: 90
+    dimensions: 320x240
+    lambda: |-
+      it.filled_rectangle(0, 0, 40, 20, Color(0xFF, 0x80, 0x00));
+
+esphome:
+  # A name of your own is only good for one snapshot - a second one under the same name fails
+  # rather than writing over the first - so these run once rather than on a repeating interval.
+  on_boot:
+    - delay: 2s
+    - snapshot.take:
+        id: snapshot_display
+        filename: test_card.bmp
+    - snapshot.take:
+        id: snapshot_rotated
+        filename: !lambda 'return "rotated.bmp";'
+
+interval:
+  # A generated name has the time in it, so this one can repeat.
+  - interval: 10s
+    then:
+      - snapshot.take: snapshot_display

tests/components/snapshot/test.host.yaml

@@ -0,0 +1,5 @@
+host:
+  mac_address: "62:23:45:AF:B3:DE"
+
+packages:
+  snapshot: !include common.yaml