When you are deploying vector shapes (e.g., rectangles, circles, or custom polygons) onto a PDF or image file using the macOS Preview application, the Core Graphics engine mathematically defaults to rendering these shapes as transparent, hollow outlines with a solid geometric border. To force the engine to violently inject a solid color matrix into the hollow void of the vector shape, you must deploy the Fill Color override.
Deploying the Vector Fill Matrix
The Preview engine contains a deeply embedded vector rendering subroutine that allows you to independently control both the stroke (border) and the fill (interior) of any mathematical shape drawn on the canvas.
- Locate your target file in Finder and double-click to open it natively in Preview.
- Look at the absolute top menu bar. Click the Show Markup Toolbar icon (it resembles a physical marker tip).
- In the newly spawned geometric toolbar, locate and click the Shapes icon (it resembles a square overlapping a circle) and draw your desired vector shape onto the canvas.
Executing the Color Injection
- Ensure the newly drawn shape is actively selected (it will be surrounded by small, blue geometric adjustment nodes).
- Look back at the Markup Toolbar. You will see two distinct color-selection icons. The icon resembling a thick, hollow square controls the Border Color. The icon resembling a solid square (often positioned to the immediate left of the border tool) controls the Fill Color.
- Click the Fill Color (solid square) icon.
- A color matrix modal will spawn. Select your desired color palette. (To completely eradicate transparency, ensure you do not select the white square with the red diagonal slash, as that is the mathematical command for “Null/Transparent”).
The exact millisecond you select a color, the Core Graphics engine intercepts the payload. It mathematically identifies the absolute inner boundaries of your vector shape and violently injects a solid pixel matrix of the chosen color into the void. This transforms the hollow outline into a dense, solid geometric object.