Provide bounding box for plain text - without tspan

While `a` element typically used together with text,
one need to have estimation of bounding box for text.
To avoid reimplementation of complete text rendering logic
just remember text position and sizes as bounding box.

Implemented only for plain text, any usage of tspan will not work properly

Author: linev

src/nodes/text.ts

@@ -24,6 +24,7 @@ interface TrimInfo {
 }
 
 export class TextNode extends GraphicsNode {
+  private boundingBox: number[] = []
   private processTSpans(
     textNode: SvgNode,
     node: Element,
@@ -159,6 +160,7 @@ export class TextNode extends GraphicsNode {
           renderingMode: textRenderingMode === 'fill' ? void 0 : textRenderingMode,
           charSpace: charSpace === 0 ? void 0 : charSpace
         })
+        this.boundingBox = [textX + dx - xOffset, textY + dy + 0.1 * pdfFontSize, context.textMeasure.measureTextWidth(transformedText, context.attributeState), pdfFontSize]
       }
     } else {
       // otherwise loop over tspans and position each relative to the previous one
@@ -228,7 +230,7 @@ export class TextNode extends GraphicsNode {
   }
 
   protected getBoundingBoxCore(context: Context): Rect {
-    return defaultBoundingBox(this.element, context)
+    return this.boundingBox.length > 0 ? this.boundingBox : defaultBoundingBox(this.element, context)
   }
 
   protected computeNodeTransformCore(context: Context): Matrix {