寻求临时隐藏及重新显示TeeChart BackImage的简便方法

Great question! I’ve dealt with this exact scenario when working with TeeChart, so let me walk you through the easiest solutions available—no need to reload images from files or streams every time.

1. Use the Built-in Visible Property (Recommended) #

Most modern versions of TeeChart include a Visible property directly on the BackImage object—this is exactly what you’re asking for! It lets you toggle the background image’s visibility without modifying the underlying bitmap at all:

// Hide the background image
Chart1.BackImage.Visible := False;

// Show it again later
Chart1.BackImage.Visible := True;

This is the most efficient method since it only controls whether the image is rendered, not loading or replacing data.

2. Cache the Image for Older TeeChart Versions #

If you’re working with an older version that doesn’t have the Visible property, you can cache the original background image in a temporary bitmap, then clear/reassign it to toggle visibility:

// First, declare a global or class-level TBitmap to hold the cached image
var
  CachedBackImage: TBitmap;

// Initialize the cache when your form/chart loads (e.g., in FormCreate)
CachedBackImage := TBitmap.Create;
CachedBackImage.Assign(Chart1.BackImage.Bitmap);

// Hide the background image
Chart1.BackImage.Bitmap.Assign(nil);

// Restore the background image later
Chart1.BackImage.Bitmap.Assign(CachedBackImage);

// Don't forget to free the cached bitmap when you're done (e.g., in FormDestroy)
CachedBackImage.Free;

This avoids the overhead of reloading from files/streams and keeps the original image intact for quick restoration.

Either of these methods will give you the clean, toggleable behavior you’re looking for—stick with the first one if your TeeChart version supports it!

内容的提问来源于stack exchange，提问作者Reron