add test for siwin popup menus

tests/tsiwin_popup_image.nim

@@ -0,0 +1,137 @@
+import std/[os, tables, unittest]
+
+import pkg/chroma
+import pkg/pixie
+
+import figdraw/commons
+import figdraw/fignodes
+import figdraw/figrender as figrender
+import figdraw/windowing/siwinshim
+
+when defined(linux) or defined(bsd):
+  import siwin/platforms
+  import siwin/platforms/x11/windowOpengl as x11WindowOpengl
+
+when UseOpenGlBackend:
+  import pkg/opengl
+  import figdraw/utils/glutils
+
+const FigdrawRoot = currentSourcePath.parentDir().parentDir()
+
+proc ensureTestOutputDir(subdir = "output"): string =
+  result = FigdrawRoot / "tests" / subdir
+  createDir(result)
+
+proc makePopupImageRenders(w, h: float32): Renders =
+  var list = RenderList()
+  let rootIdx = list.addRoot(
+    Fig(
+      kind: nkRectangle,
+      childCount: 0,
+      zlevel: 0.ZLevel,
+      screenBox: rect(0, 0, w, h),
+      fill: rgba(160, 160, 160, 255),
+    )
+  )
+
+  list.addChild(
+    rootIdx,
+    Fig(
+      kind: nkImage,
+      childCount: 0,
+      zlevel: 0.ZLevel,
+      screenBox: rect(24, 20, 96, 96),
+      image:
+        ImageStyle(fill: rgba(255, 255, 255, 255).color, id: hash("img1.png").ImageId),
+    ),
+  )
+
+  result = Renders(layers: initOrderedTable[ZLevel, RenderList]())
+  result.layers[0.ZLevel] = list
+
+proc maxChannelDelta(a: ColorRGBX, r, g, b: uint8): int =
+  max(abs(a.r.int - r.int), max(abs(a.g.int - g.int), abs(a.b.int - b.int)))
+
+proc renderPopupImageFrame(): Image =
+  let globals = newSiwinGlobals(Platform.x11)
+  var
+    parent: Window
+    popup: Window
+  try:
+    parent = globals.newOpenglWindow(
+      size = ivec2(260, 180), title = "figdraw popup image parent"
+    )
+  except CatchableError as exc:
+    raise newException(OSError, "OpenGL X11 window unavailable: " & exc.msg)
+
+  try:
+    parent.firstStep(makeVisible = false)
+    parent.step()
+    startOpenGL(openglVersion)
+
+    let placement = PopupPlacement(
+      anchorRectPos: ivec2(36, 48),
+      anchorRectSize: ivec2(120, 32),
+      size: ivec2(180, 140),
+      anchor: bottomLeft,
+      gravity: topLeft,
+      offset: ivec2(0, 8),
+    )
+    popup = globals.newPopupWindow(parent, placement, grab = false)
+    if not (popup of x11WindowOpengl.WindowX11Opengl):
+      raise
+        newException(ValueError, "X11 OpenGL popup did not preserve OpenGL window type")
+    popup.firstStep(makeVisible = false)
+
+    let renderer =
+      figrender.newFigRenderer(atlasSize = 512, backendState = SiwinRenderBackend())
+    renderer.setupBackend(popup)
+    renderer.beginFrame()
+    let sz = popup.logicalSize()
+    var renders = makePopupImageRenders(sz.x, sz.y)
+    renderer.renderFrame(renders, sz)
+    glFinish()
+    result = figrender.takeOneFrameScreenshot(renderer)
+    renderer.endFrame()
+  finally:
+    if not popup.isNil:
+      close popup
+    if not parent.isNil:
+      close parent
+
+suite "figdraw siwin popup image render":
+  test "renders an image into an X11 OpenGL popup":
+    when UseOpenGlBackend and (defined(linux) or defined(bsd)):
+      if Platform.x11 notin availablePlatforms():
+        skip()
+
+      setFigDataDir(FigdrawRoot / "data")
+      discard loadImage("img1.png")
+      let outPath = ensureTestOutputDir() / "siwin_popup_image.png"
+      if fileExists(outPath):
+        removeFile(outPath)
+
+      block renderOnce:
+        var img: Image
+        try:
+          img = renderPopupImageFrame()
+        except OSError:
+          skip()
+          break renderOnce
+
+        img.writeFile(outPath)
+        check fileExists(outPath)
+        check getFileSize(outPath) > 0
+        check img.width == 180
+        check img.height == 140
+
+        let bg = (r: 160'u8, g: 160'u8, b: 160'u8)
+        var differsFromBg = false
+        for y in 28 .. 88:
+          for x in 32 .. 96:
+            if img[x, y].maxChannelDelta(bg.r, bg.g, bg.b) > 12:
+              differsFromBg = true
+
+        check differsFromBg
+    else:
+      skip()