AResolution contains the TCustomImageListResolution -instance with image data used as the source for the scaled images. +instance with image data used as the source for the Scaled images. AResolution is stored in the Resolution property to provide access to its properties and methods in the scaled image resolution.
@@ -2757,6 +2758,7 @@ GetResolutionForPPI is used in the implementation of the DrawForPPI method.WidthForPPI is an indexed read-only Integer property that contains -the image width needed for images using the specified display density (Pixels +the widths needed for images using the specified display densities (Pixels per Inch).
@@ -6133,7 +6135,10 @@ calculate the width of images. Reading the value for the property causes the image width to be calculated using the specified parameter values. If AWidth is 0 (zero) or a negative number, the value in the Width property is used as the initial -image width. When Scaled contains True, the image width is +image width. +
++When Scaled contains True, the image width is calculated using the following formula:
(AImageWidth * APPI) / 96
@@ -6170,7 +6175,7 @@ and the value in AImageWidth is used as the property value.
The OnGetWidthForPPI event handler is signalled (when assigned) to -allow overriding the calculated image width. Applications can provide a +allow the calculated image width to be overridden. Applications can provide a TCustomImageListGetWidthForPPI procedure which uses custom scaling logic, or performs simple image width substitution for given display densities. @@ -6412,6 +6417,7 @@ using the specified display density.
-Scaled is a Boolean property that indicates if images -are automatically scaled for missing resolutions requested in the image list. -The default value for the property is False. +Scaled is a Boolean property used to enable or disable +automatic scaling of image sizes for different resolutions (Pixels per Inch).
-When Scaled contains True, images in the list are dynamically scaled -to the required width for a given display density (PPI). If the resolution -already exists in the image list, it is used to retrieve images. If it does -not already exist, an existing resolution is used as the basis for scaling -images to the required width. When Scaled contains False, dynamic -scaling is not performed for image resolutions. Instead, the closest -resolution that matches the desired width is used as the source for images. +When Scaled is True, images in the list are dynamically scaled from the +Width and Height used in the image list to the size needed for a given display +density (Pixels per Inch). If the scaled image size is one of the Resolutions +found in the image list, the images in the Resolution are used. If an image +size is needed that does not exist in Resolutions, the next smaller size is +selected from the predefined images by using the WidthForPPI property and a +specified PPI setting. The ResolutionForPPI property provides access to an +image list using the scaled image size.
-Use the OnGetWidthForPPI event handler to perform image size -overrides or substitution for a given display density (PPI). +See WidthForPPI for information +about use of the pixels per inch setting to derive the scaling factor and the +resulting size for images. +
++When Scaled is False, images are not dynamically scaled. The Width and +Height specified in the image list are used. +
++The default value for the property is False and disables automatic +scaling. +
++At design-time, use the image list property editor to maintain images or +resolutions used in the image list. At run-time, use the methods provided in +the class instance to maintain the image list. +
++Use the OnGetWidthForPPI event handler to override or substitute the +image size used for a given display density (PPI).
Scaled is used in the implementation of the GetResolutionForPPI -and GetWidthForPPI methods. +and GetWidthForPPI methods which implement the ResolutionForPPI and +WidthForPPI properties (respectively).