docs: mention direnv in README bootstrap section

Provide a reproducible dev shell with JDK 17 and Maven 3.9.x.
JDK 17 (LTS) is used since JDK 16 (project target) is non-LTS
and unavailable in nixpkgs; it is fully backward-compatible with
--source 16 --target 16. Maven is overridden via overlay to use
the same JDK.

.envrc

@@ -0,0 +1 @@
+use flake

README.md

@@ -0,0 +1,54 @@
+# new-shapes
+
+A shape editor desktop application built with Java Swing. Supports rectangles, circles, triangles, text, shape collections, resize handles, and export to HTML/SVG.
+
+## Prerequisites
+
+- JDK >= 16 (project targets Java 16)
+- A graphical display (X11/Wayland) since this is a Swing GUI application
+
+## Bootstrap
+
+### With Nix (recommended)
+
+If you have [direnv](https://direnv.net/) installed, the environment activates automatically:
+
+```sh
+direnv allow   # one-time, then auto-activates on cd
+```
+
+Otherwise, enter the dev shell manually:
+
+```sh
+nix develop
+```
+
+Both provide JDK 17 and Maven 3.9.x preconfigured. No other setup needed.
+
+### Without Nix
+
+Install JDK 16+ and use the bundled Maven wrapper — no separate Maven installation required:
+
+```sh
+./mvnw --version   # downloads Maven 3.9.12 on first run
+```
+
+## Run the application
+
+```sh
+./mvnw compile exec:java -Dexec.mainClass="ovh.gasser.newshapes.App"
+```
+
+## Run tests
+
+```sh
+./mvnw test
+```
+
+To run the full verification pipeline (compile, test, JaCoCo coverage check with 50% minimum line coverage):
+
+```sh
+./mvnw verify
+```
+
+Coverage reports are generated in `target/site/jacoco/`.

flake.lock

@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1774386573,
+        "narHash": "sha256-4hAV26quOxdC6iyG7kYaZcM3VOskcPUrdCQd/nx8obc=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "46db2e09e1d3f113a13c0d7b81e2f221c63b8ce9",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,48 @@
+{
+  description = "new-shapes - Java Swing shape editor";
+
+  inputs.nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+
+  outputs = { self, nixpkgs }:
+    let
+      # JDK 16 (project target) is non-LTS and unavailable in nixpkgs.
+      # JDK 17 (LTS) is fully backward-compatible with --source 16 --target 16.
+      javaVersion = 17;
+
+      supportedSystems = [ "x86_64-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin" ];
+
+      forEachSystem = f:
+        nixpkgs.lib.genAttrs supportedSystems (system: f {
+          pkgs = import nixpkgs {
+            inherit system;
+            overlays = [ self.overlays.default ];
+          };
+        });
+    in
+    {
+      overlays.default = final: prev:
+        let
+          jdk = prev."jdk${toString javaVersion}";
+        in
+        {
+          inherit jdk;
+          # Override Maven to use the same JDK version
+          maven = prev.maven.override { jdk_headless = jdk; };
+        };
+
+      devShells = forEachSystem ({ pkgs }: {
+        default = pkgs.mkShell {
+          packages = with pkgs; [
+            jdk
+            maven
+          ];
+
+          shellHook = ''
+            echo "new-shapes dev shell"
+            echo "  Java: $(java -version 2>&1 | head -1)"
+            echo "  Maven: $(mvn -version 2>&1 | head -1)"
+          '';
+        };
+      });
+    };
+}

src/test/java/ovh/gasser/newshapes/shapes/ResizeHandleTest.java

@@ -0,0 +1,94 @@
+package ovh.gasser.newshapes.shapes;
+
+import org.junit.jupiter.api.Test;
+import java.awt.Cursor;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class ResizeHandleTest {
+
+    @Test
+    void testEightHandlesExist() {
+        assertEquals(8, ResizeHandle.values().length,
+                "ResizeHandle enum should define exactly 8 handles");
+    }
+
+    @Test
+    void testAllHandleNamesExist() {
+        assertNotNull(ResizeHandle.valueOf("NW"), "Handle NW should exist");
+        assertNotNull(ResizeHandle.valueOf("N"),  "Handle N should exist");
+        assertNotNull(ResizeHandle.valueOf("NE"), "Handle NE should exist");
+        assertNotNull(ResizeHandle.valueOf("E"),  "Handle E should exist");
+        assertNotNull(ResizeHandle.valueOf("SE"), "Handle SE should exist");
+        assertNotNull(ResizeHandle.valueOf("S"),  "Handle S should exist");
+        assertNotNull(ResizeHandle.valueOf("SW"), "Handle SW should exist");
+        assertNotNull(ResizeHandle.valueOf("W"),  "Handle W should exist");
+    }
+
+    @Test
+    void testNwMapsToCorrectCursorType() {
+        assertEquals(Cursor.NW_RESIZE_CURSOR, ResizeHandle.NW.getCursorType(),
+                "NW handle should map to Cursor.NW_RESIZE_CURSOR");
+    }
+
+    @Test
+    void testNMapsToCorrectCursorType() {
+        assertEquals(Cursor.N_RESIZE_CURSOR, ResizeHandle.N.getCursorType(),
+                "N handle should map to Cursor.N_RESIZE_CURSOR");
+    }
+
+    @Test
+    void testNeMapsToCorrectCursorType() {
+        assertEquals(Cursor.NE_RESIZE_CURSOR, ResizeHandle.NE.getCursorType(),
+                "NE handle should map to Cursor.NE_RESIZE_CURSOR");
+    }
+
+    @Test
+    void testEMapsToCorrectCursorType() {
+        assertEquals(Cursor.E_RESIZE_CURSOR, ResizeHandle.E.getCursorType(),
+                "E handle should map to Cursor.E_RESIZE_CURSOR");
+    }
+
+    @Test
+    void testSeMapsToCorrectCursorType() {
+        assertEquals(Cursor.SE_RESIZE_CURSOR, ResizeHandle.SE.getCursorType(),
+                "SE handle should map to Cursor.SE_RESIZE_CURSOR");
+    }
+
+    @Test
+    void testSMapsToCorrectCursorType() {
+        assertEquals(Cursor.S_RESIZE_CURSOR, ResizeHandle.S.getCursorType(),
+                "S handle should map to Cursor.S_RESIZE_CURSOR");
+    }
+
+    @Test
+    void testSwMapsToCorrectCursorType() {
+        assertEquals(Cursor.SW_RESIZE_CURSOR, ResizeHandle.SW.getCursorType(),
+                "SW handle should map to Cursor.SW_RESIZE_CURSOR");
+    }
+
+    @Test
+    void testWMapsToCorrectCursorType() {
+        assertEquals(Cursor.W_RESIZE_CURSOR, ResizeHandle.W.getCursorType(),
+                "W handle should map to Cursor.W_RESIZE_CURSOR");
+    }
+
+    @Test
+    void testValueOfReturnsCorrectConstant() {
+        assertSame(ResizeHandle.NW, ResizeHandle.valueOf("NW"), "valueOf(\"NW\") should return ResizeHandle.NW");
+        assertSame(ResizeHandle.N,  ResizeHandle.valueOf("N"),  "valueOf(\"N\") should return ResizeHandle.N");
+        assertSame(ResizeHandle.NE, ResizeHandle.valueOf("NE"), "valueOf(\"NE\") should return ResizeHandle.NE");
+        assertSame(ResizeHandle.E,  ResizeHandle.valueOf("E"),  "valueOf(\"E\") should return ResizeHandle.E");
+        assertSame(ResizeHandle.SE, ResizeHandle.valueOf("SE"), "valueOf(\"SE\") should return ResizeHandle.SE");
+        assertSame(ResizeHandle.S,  ResizeHandle.valueOf("S"),  "valueOf(\"S\") should return ResizeHandle.S");
+        assertSame(ResizeHandle.SW, ResizeHandle.valueOf("SW"), "valueOf(\"SW\") should return ResizeHandle.SW");
+        assertSame(ResizeHandle.W,  ResizeHandle.valueOf("W"),  "valueOf(\"W\") should return ResizeHandle.W");
+    }
+
+    @Test
+    void testValueOfWithInvalidNameThrowsIllegalArgumentException() {
+        assertThrows(IllegalArgumentException.class,
+                () -> ResizeHandle.valueOf("INVALID"),
+                "valueOf() with an unknown name should throw IllegalArgumentException");
+    }
+}

src/test/java/ovh/gasser/newshapes/ui/visitors/HTMLDraftmanTest.java

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+package ovh.gasser.newshapes.ui.visitors;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+import ovh.gasser.newshapes.attributes.ColorAttributes;
+import ovh.gasser.newshapes.shapes.*;
+
+import java.awt.*;
+import java.io.PrintWriter;
+import java.io.StringWriter;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class HTMLDraftmanTest {
+
+    private StringWriter htmlBuffer;
+    private StringWriter cssBuffer;
+    private PrintWriter htmlWriter;
+    private PrintWriter cssWriter;
+    private HTMLDraftman draftman;
+
+    @BeforeEach
+    void setUp() {
+        htmlBuffer = new StringWriter();
+        cssBuffer = new StringWriter();
+        htmlWriter = new PrintWriter(htmlBuffer);
+        cssWriter = new PrintWriter(cssBuffer);
+        draftman = new HTMLDraftman(htmlWriter, cssWriter);
+    }
+
+    private String html() {
+        htmlWriter.flush();
+        return htmlBuffer.toString();
+    }
+
+    private String css() {
+        cssWriter.flush();
+        return cssBuffer.toString();
+    }
+
+    // ── visitRectangle ──────────────────────────────────────────────
+
+    @Nested
+    class VisitRectangleTests {
+
+        @Test
+        void testRectangleProducesDivWithId() {
+            SRectangle rect = SRectangle.create(10, 20, 100, 50);
+            draftman.visitRectangle(rect);
+
+            assertTrue(html().contains("<div id=\"rec"), "Should produce a div with rec id");
+        }
+
+        @Test
+        void testRectangleCssContainsCorrectPosition() {
+            SRectangle rect = SRectangle.create(10, 20, 100, 50);
+            draftman.visitRectangle(rect);
+
+            String cssOut = css();
+            assertTrue(cssOut.contains("top:20px"), "CSS should contain correct top");
+            assertTrue(cssOut.contains("left:10px"), "CSS should contain correct left");
+        }
+
+        @Test
+        void testRectangleCssContainsCorrectDimensions() {
+            SRectangle rect = SRectangle.create(10, 20, 100, 50);
+            draftman.visitRectangle(rect);
+
+            String cssOut = css();
+            assertTrue(cssOut.contains("width:100px"), "CSS should contain correct width");
+            assertTrue(cssOut.contains("height:50px"), "CSS should contain correct height");
+        }
+
+        @Test
+        void testRectangleCssPositionIsAbsolute() {
+            SRectangle rect = SRectangle.create(0, 0, 30, 30);
+            draftman.visitRectangle(rect);
+
+            assertTrue(css().contains("position:absolute"), "CSS should use absolute positioning");
+        }
+
+        @Test
+        void testRectangleHtmlIdMatchesCssSelector() {
+            SRectangle rect = SRectangle.create(0, 0, 30, 30);
+            draftman.visitRectangle(rect);
+
+            String id = "rec" + rect.hashCode();
+            assertTrue(html().contains("id=\"" + id + "\""), "HTML should contain div with correct id");
+            assertTrue(css().contains("#" + id), "CSS should reference same id");
+        }
+
+        @Test
+        void testRectangleFilledAndStroked() {
+            SRectangle rect = SRectangle.create(0, 0, 30, 30);
+            rect.addAttributes(new ColorAttributes(true, true, Color.RED, Color.BLUE));
+            draftman.visitRectangle(rect);
+
+            String cssOut = css();
+            assertTrue(cssOut.contains("background:"), "CSS should contain background");
+            assertTrue(cssOut.contains("border:"), "CSS should contain border");
+        }
+
+        @Test
+        void testRectangleFilledOnly() {
+            SRectangle rect = SRectangle.create(0, 0, 30, 30);
+            rect.addAttributes(new ColorAttributes(true, false, Color.RED, Color.BLACK));
+            draftman.visitRectangle(rect);
+
+            String cssOut = css();
+            assertTrue(cssOut.contains("background:"), "CSS should contain background for filled");
+            assertFalse(cssOut.contains("border:"), "CSS should not contain border when not stroked");
+        }
+
+        @Test
+        void testRectangleStrokedOnly() {
+            SRectangle rect = SRectangle.create(0, 0, 30, 30);
+            rect.addAttributes(new ColorAttributes(false, true, Color.RED, Color.BLUE));
+            draftman.visitRectangle(rect);
+
+            String cssOut = css();
+            assertTrue(cssOut.contains("border:"), "CSS should contain border for stroked");
+            assertTrue(cssOut.contains("background:#ffffff"), "CSS should have white background when not filled");
+        }
+
+        @Test
+        void testRectangleNeitherFilledNorStroked() {
+            SRectangle rect = SRectangle.create(0, 0, 30, 30);
+            rect.addAttributes(new ColorAttributes(false, false, Color.RED, Color.BLUE));
+            draftman.visitRectangle(rect);
+
+            String cssOut = css();
+            assertFalse(cssOut.contains("background:"), "CSS should not contain background");
+            assertFalse(cssOut.contains("border:"), "CSS should not contain border");
+        }
+    }
+
+    // ── visitCircle ─────────────────────────────────────────────────
+
+    @Nested
+    class VisitCircleTests {
+
+        @Test
+        void testCircleProducesDivWithClass() {
+            SCircle circle = SCircle.create(50, 60, 30);
+            draftman.visitCircle(circle);
+
+            assertTrue(html().contains("circle"), "HTML should contain circle class div");
+        }
+
+        @Test
+        void testCircleCssContainsBorderRadius() {
+            SCircle circle = SCircle.create(50, 60, 30);
+            draftman.visitCircle(circle);
+
+            String cssOut = css();
+            assertTrue(cssOut.contains("border-radius:"), "CSS should contain border-radius");
+            assertTrue(cssOut.contains("-webkit-border-radius:"), "CSS should contain webkit prefix");
+            assertTrue(cssOut.contains("-moz-border-radius:"), "CSS should contain moz prefix");
+        }
+
+        @Test
+        void testCircleCssContainsCorrectPosition() {
+            SCircle circle = SCircle.create(50, 60, 30);
+            draftman.visitCircle(circle);
+
+            String cssOut = css();
+            assertTrue(cssOut.contains("top:60px"), "CSS should contain correct top");
+            assertTrue(cssOut.contains("left:50px"), "CSS should contain correct left");
+        }
+
+        @Test
+        void testCircleHtmlClassMatchesCssSelector() {
+            SCircle circle = SCircle.create(0, 0, 20);
+            draftman.visitCircle(circle);
+
+            String className = "circle" + circle.hashCode();
+            assertTrue(html().contains(className), "HTML should have circle class");
+            assertTrue(css().contains("." + className), "CSS should reference same class");
+        }
+    }
+
+    // ── visitTriangle ───────────────────────────────────────────────
+
+    @Nested
+    class VisitTriangleTests {
+
+        @Test
+        void testTriangleProducesDivWithClass() {
+            STriangle tri = STriangle.create(10, 20, 40, Color.RED, Color.BLACK);
+            draftman.visitTriangle(tri);
+
+            assertTrue(html().contains("triangle"), "HTML should contain triangle class div");
+        }
+
+        @Test
+        void testTriangleCssContainsBorderTrick() {
+            STriangle tri = STriangle.create(10, 20, 40, Color.RED, Color.BLACK);
+            draftman.visitTriangle(tri);
+
+            String cssOut = css();
+            assertTrue(cssOut.contains("border-left-width:"), "CSS should use border-left-width");
+            assertTrue(cssOut.contains("border-right-width:"), "CSS should use border-right-width");
+            assertTrue(cssOut.contains("border-bottom:"), "CSS should use border-bottom");
+            assertTrue(cssOut.contains("width: 0px"), "CSS should set width to 0");
+            assertTrue(cssOut.contains("height: 0px"), "CSS should set height to 0");
+        }
+
+        @Test
+        void testTriangleCssContainsCorrectPosition() {
+            STriangle tri = STriangle.create(10, 20, 40, Color.RED, Color.BLACK);
+            draftman.visitTriangle(tri);
+
+            String cssOut = css();
+            assertTrue(cssOut.contains("top: 20px"), "CSS should contain correct top");
+            assertTrue(cssOut.contains("left: 10px"), "CSS should contain correct left");
+        }
+
+        @Test
+        void testTriangleCssContainsFillColor() {
+            STriangle tri = STriangle.create(0, 0, 20, Color.BLUE, Color.BLACK);
+            tri.addAttributes(new ColorAttributes(true, false, Color.BLUE, Color.BLACK));
+            draftman.visitTriangle(tri);
+
+            assertTrue(css().contains("#0000ff"), "CSS should contain the triangle fill color");
+        }
+
+        @Test
+        void testTriangleHtmlClassMatchesCssSelector_regressionHashCode() {
+            // Regression test: visitTriangle previously used this.hashCode()
+            // instead of sTriangle.hashCode(), causing HTML class and CSS
+            // selector mismatch when rendered by a different draftman instance.
+            STriangle tri = STriangle.create(5, 5, 30, Color.RED, Color.BLACK);
+            draftman.visitTriangle(tri);
+
+            String htmlOut = html();
+            String cssOut = css();
+
+            // Extract the class name from HTML: class="triangleNNN"
+            int classStart = htmlOut.indexOf("triangle");
+            assertNotEquals(-1, classStart, "HTML should contain triangle class");
+            int classEnd = htmlOut.indexOf("\"", classStart);
+            String htmlClassName = htmlOut.substring(classStart, classEnd);
+
+            // CSS should use the same class name
+            assertTrue(cssOut.contains("." + htmlClassName),
+                    "CSS selector should match HTML class — " +
+                    "if this fails, visitTriangle may be using this.hashCode() instead of sTriangle.hashCode()");
+        }
+    }
+
+    // ── visitText ───────────────────────────────────────────────────
+
+    @Nested
+    class VisitTextTests {
+
+        @Test
+        void testTextProducesDivWithContent() {
+            SText text = SText.create(10, 20, "Hello");
+            draftman.visitText(text);
+
+            assertTrue(html().contains(">Hello</div>"), "HTML should contain text content in div");
+        }
+
+        @Test
+        void testTextHtmlIdMatchesCssSelector() {
+            SText text = SText.create(0, 0, "Test");
+            draftman.visitText(text);
+
+            String id = "txt" + text.hashCode();
+            assertTrue(html().contains("id=\"" + id + "\""), "HTML should contain text div with correct id");
+            assertTrue(css().contains("#" + id), "CSS should reference same text id");
+        }
+
+        @Test
+        void testTextCssContainsPosition() {
+            SText text = SText.create(15, 25, "Pos");
+            draftman.visitText(text);
+
+            String cssOut = css();
+            assertTrue(cssOut.contains("top:25px"), "CSS should contain correct top");
+            assertTrue(cssOut.contains("left:15px"), "CSS should contain correct left");
+        }
+
+        @Test
+        void testTextCssContainsDefaultFontAttributes() {
+            SText text = SText.create(0, 0, "Font");
+            draftman.visitText(text);
+
+            String cssOut = css();
+            assertTrue(cssOut.contains("font-family:"), "CSS should contain font-family");
+            assertTrue(cssOut.contains("font-size:16px"), "CSS should contain default font size");
+            assertTrue(cssOut.contains("font-style:normal"), "CSS should contain normal font style");
+            assertTrue(cssOut.contains("font-weight:normal"), "CSS should contain normal font weight");
+        }
+
+        @Test
+        void testTextCssContainsColor() {
+            SText text = SText.create(0, 0, "Colored");
+            text.addAttributes(new ColorAttributes(true, false, Color.RED, Color.BLACK));
+            draftman.visitText(text);
+
+            assertTrue(css().contains("color:#ff0000"), "CSS should contain fill color as text color");
+        }
+
+        @Test
+        void testTextCssWhiteSpaceNowrap() {
+            SText text = SText.create(0, 0, "NoWrap");
+            draftman.visitText(text);
+
+            assertTrue(css().contains("white-space: nowrap"), "CSS should prevent text wrapping");
+        }
+
+        @Test
+        void testTextWithNullColorAttributesFallsBackToBlack() {
+            SText text = SText.create(0, 0, "Fallback");
+            text.addAttributes(new ColorAttributes(false, false, null, null));
+            draftman.visitText(text);
+
+            assertTrue(css().contains("color:#000000"), "Should fall back to black with null colors");
+        }
+    }
+
+    // ── visitCollection ─────────────────────────────────────────────
+
+    @Nested
+    class VisitCollectionTests {
+
+        @Test
+        void testEmptyCollection() {
+            SCollection empty = SCollection.of();
+            draftman.visitCollection(empty);
+
+            assertEquals("", html(), "Empty collection should produce no HTML");
+            assertEquals("", css(), "Empty collection should produce no CSS");
+        }
+
+        @Test
+        void testCollectionVisitsAllChildren() {
+            SCollection coll = SCollection.of(
+                    SRectangle.create(0, 0, 10, 10),
+                    SCircle.create(20, 20, 5)
+            );
+            draftman.visitCollection(coll);
+
+            assertTrue(html().contains("rec"), "Should visit rectangle");
+            assertTrue(html().contains("circle"), "Should visit circle");
+        }
+
+        @Test
+        void testNestedCollectionVisitsAllDescendants() {
+            SCollection inner = SCollection.of(
+                    SRectangle.create(0, 0, 5, 5)
+            );
+            SCollection outer = SCollection.of(
+                    inner,
+                    SCircle.create(10, 10, 3)
+            );
+            draftman.visitCollection(outer);
+
+            assertTrue(html().contains("rec"), "Should visit nested rectangle");
+            assertTrue(html().contains("circle"), "Should visit circle at outer level");
+        }
+    }
+
+    // ── generateHTML ────────────────────────────────────────────────
+
+    @Nested
+    class GenerateHTMLTests {
+
+        @Test
+        void testGenerateHTMLIncludesDoctype() {
+            SCollection model = SCollection.of();
+            draftman.generateHTML(model);
+
+            assertTrue(html().contains("<!DOCTYPE html>"), "Should include DOCTYPE");
+        }
+
+        @Test
+        void testGenerateHTMLIncludesHtmlStructure() {
+            SCollection model = SCollection.of();
+            draftman.generateHTML(model);
+
+            String htmlOut = html();
+            assertTrue(htmlOut.contains("<html"), "Should include html tag");
+            assertTrue(htmlOut.contains("<head>"), "Should include head tag");
+            assertTrue(htmlOut.contains("<body>"), "Should include body tag");
+            assertTrue(htmlOut.contains("</body>"), "Should close body tag");
+        }
+
+        @Test
+        void testGenerateHTMLReferencesStylesheet() {
+            SCollection model = SCollection.of();
+            draftman.generateHTML(model);
+
+            assertTrue(html().contains("style.css"), "Should reference CSS stylesheet");
+        }
+
+        @Test
+        void testGenerateHTMLIncludesShapeContent() {
+            SCollection model = SCollection.of(
+                    SRectangle.create(1, 2, 3, 4)
+            );
+            draftman.generateHTML(model);
+
+            assertTrue(html().contains("<div id=\"rec"), "Should include shape elements");
+        }
+    }
+}