Add screenshot for take screenshot of page.

Dockerfile

@@ -12,6 +12,7 @@ RUN make build
 FROM debian:bullseye-slim
 
 RUN apt-get update \
+    && apt-get install -y fonts-noto-cjk \
     && apt-get install -y chromium \
     && apt-get clean \
     && rm -rf /var/lib/apt/lists/*

README.md

@@ -984,6 +984,16 @@ actions:
   - outerHTML: 'h1'
 ```
 
+**`screenshot`** (aliases: `getScreenshot`)
+
+Take a full screenshot of the entire browser viewport.
+
+```yaml
+actions:
+  - screenshot:
+# record to current.png:
+```
+
 **`sendKeys`**
 
 Send keys (`value`) to the first element node matching the selector (`sel`).

cdp.go

@@ -101,6 +101,8 @@ func (rnr *cdpRunner) Run(_ context.Context, cas CDPActions) error {
 					res[arg.Key] = *vv
 				case *map[string]string:
 					res[arg.Key] = *vv
+				case *[]byte:
+					res[arg.Key] = *vv
 				default:
 					res[arg.Key] = vv
 				}
@@ -117,6 +119,8 @@ func (rnr *cdpRunner) Run(_ context.Context, cas CDPActions) error {
 			r[k] = *vv
 		case *map[string]string:
 			r[k] = *vv
+		case *[]byte:
+			r[k] = *vv
 		default:
 			r[k] = vv
 		}
@@ -155,6 +159,10 @@ func (rnr *cdpRunner) evalAction(ca CDPAction) (chromedp.Action, error) {
 				v := map[string]string{}
 				rnr.store[k] = &v
 				vs = append(vs, reflect.ValueOf(&v))
+			case reflect.Slice:
+				var v []byte
+				rnr.store[k] = &v
+				vs = append(vs, reflect.ValueOf(&v))
 			default:
 				return nil, fmt.Errorf("invalid action: %v", ca)
 			}

cdpfn.go

@@ -193,6 +193,16 @@ var CDPFnMap = map[string]CDPFn{
 		},
 		Aliases: []string{"getAttributes", "attrs", "getAttrs"},
 	},
+	"screenshot": {
+		Desc: "Take a full screenshot of the entire browser viewport.",
+		Fn: func(b *[]byte) chromedp.Action {
+			return chromedp.FullScreenshot(b, 100)
+		},
+		Args: CDPFnArgs{
+			{CDPArgTypeRes, "png", "[]byte"},
+		},
+		Aliases: []string{"getScreenshot"},
+	},
 	"evaluate": {
 		Desc: "Evaluate the Javascript expression (`expr`).",
 		Fn: func(expr string) chromedp.Action {