ci: Create layout image with klayout

diff --git a/.github/workflows/user_project_ci.yml b/.github/workflows/user_project_ci.yml
index feb6f2e..cd20cfd 100644
--- a/.github/workflows/user_project_ci.yml
+++ b/.github/workflows/user_project_ci.yml

@@ -206,27 +206,15 @@
           verilog/
           openlane/tiny_user_project/runs/tiny_user_project/tmp/synthesis/post_techmap.dot
         key: ${{ runner.os }}-gds-${{ github.run_id }}
-    - name: create layout svg
+    - name: create layout png
       run: |
-        python -m pip install gdstk
-        python << EOF
-        import gdstk
-        library = gdstk.read_gds('gds/tiny_user_project.gds')
-        top_cells = library.top_level()
-        top_cells[0].write_svg('tiny_user_project_layout.svg')
-        EOF
-    - name: convert to png
-      run: |
-        python -m pip install cairosvg
-        python << EOF
-        import cairosvg
-        cairosvg.svg2png(url='tiny_user_project_layout.svg', write_to='tiny_user_project_layout.png')
-        EOF
+        klayout -l ${{ env.PDK_ROOT }}/${{ env.PDK }}/libs.tech/klayout/tech/gf180mcu.lyp gds/tiny_user_project.gds -z -r scripts/create_svg.py
+
     - name: populate img cache
       uses: actions/cache@v3
       with:
         path: |
-          tiny_user_project_layout.png
+          layout.png
         key: ${{ runner.os }}-img-${{ github.run_id }}
 
   pages:
@@ -244,7 +232,7 @@
       uses: actions/cache@v3
       with:
         path: |
-          tiny_user_project_layout.png
+          layout.png
         key: ${{ runner.os }}-img-${{ github.run_id }}
     - name: setup pages
       uses: actions/configure-pages@v2
@@ -266,5 +254,5 @@
         PAGE_URL=$(echo "$PAGE_URL" | sed -e 's/\/$//')
         cat << EOF >> $GITHUB_STEP_SUMMARY
         # layout
-        ![layout]($PAGE_URL/tiny_user_project_layout.png)
+        ![layout]($PAGE_URL/layout.png)
         EOF

diff --git a/scripts/create_svg.py b/scripts/create_svg.py
deleted file mode 100644
index 0bac98b..0000000
--- a/scripts/create_svg.py
+++ /dev/null

@@ -1,8 +0,0 @@
-import gdstk
-import pathlib
-gds = sorted(pathlib.Path('.').glob('gds/tiny_user_project.gds'))
-library = gdstk.read_gds(gds[-1])
-top_cells = library.top_level()
-top_cells[0].write_svg('gds_render.svg')
-import cairosvg
-cairosvg.svg2png(url='gds_render.svg', write_to='gds_render.png')
\ No newline at end of file

diff --git a/scripts/klayout_save_image.py b/scripts/klayout_save_image.py
new file mode 100644
index 0000000..9f68f15
--- /dev/null
+++ b/scripts/klayout_save_image.py

@@ -0,0 +1,28 @@
+# SPDX-FileCopyrightText: 2022 Greg Davill
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+lv = pya.LayoutView.current()
+ly = pya.CellView.active().layout()
+
+# top cell bounding box in micrometer units
+bbox = ly.top_cell().dbbox()
+
+# compute an image size having the same aspect ratio than 
+# the bounding box
+w = 1200
+h = int(0.5 + w * bbox.height() / bbox.width())
+
+lv.save_image_with_options('layout.png', w, h, 0, 0, 0, bbox, False)