Introduction to Delphi xe2 firemonkey (15)-filter: Get filter information

Inheritance of filter classes:

 
Tobject-> tpersistent-> tfilter-> tshaderfilter-> {Specific filter class} // The following example uses FMX first. four common methods of filter unit: Procedure fillcategory (alist: tstrings); Procedure fillfiltersincategory (const category: string; alist: tstrings); function filterbyname (const aname: string): tfilter; function filterclassbyname (const aname: string): tfilterclass;
 

The fillcategory () method can be used to obtain the filter category list:

 
Fillcategory (listbox1.items );
 

You can use the fillfiltersincategory () method to obtain the Filter list of a category:

 
Fillfiltersincategory ('category name', listbox2.items );
 

You can use the filterbyname () method to obtain the filter object:

VaR filter: tfilter; begin filter: = filterbyname ('filter name'); // This is convenient, saving the need to manually create an end;
 

You can use the filterattr () method of tfilter to obtain the filter information:

 
VaR filter: tfilter; filterrec: tfilterrec; // filter information is encapsulated in a tfilterrec-type struct. Begin filter: = filterbyname ('filter name'); filterrec: = filter. filterattr; {because filterattr is a class method, you can also obtain it as follows} filterrec: = filterclassbyname ('filter name '). filterattr; end;
 

Tfilterrec structure:

 
Tfilterrec = Record Name: string; // Filter Name Desc: string; // filter description values: tshadervaluerecarray; // filter parameter array, tshadervaluerec type end;
 

Tshadervaluerec structure:

Tshadervaluerec = Record Name: string; // parameter name Desc: string; // parameter description valuetype: tshadervaluetype; // parameter type: vtfloat, vtpoint, vtcolor, vtbitmap (value, point, color value, image) value: variant; // parameter value min, Max, default: variant; // The minimum, maximum, and default value of the parameter end;
 

Test: Two tlistbox, one tmemo, and oncreate and tlistbox onclick events are required.

Uses system. typinfo; // used to obtain the enumeration name procedure tform1.formcreate (Sender: tobject); begin fillcategory (listbox1.items); // get the category name list end; Procedure tform1.listbox1click (Sender: tobject ); vaR stritem1: string; begin stritem1: = listbox1.items [listbox1.itemindex]; iterator (stritem1, listbox2.items); // obtain the Filter list listbox2.itemindex: = 0; listbox2.onclick (NiL) of the specified category ); end; Procedure extract (Sender: tobject); var stritem2: string; filter: tfilter; filterrec: tfilterrec; shadervaluerec: iterator; begin stritem2: = listbox2.items [listbox2.itemindex]; filter: = filterbyname (stritem2); // obtain the filter object filterrec: = Filter Using the Filter Name. filterattr; // get the information of the filter object // filterrec: = filterclassbyname (stritem ). filterattr; // memo1.text: = 'filter Class Name: '+ filter. tostring; // classname memo1.lines. add ('filter name: '+ filterrec. name); memo1.lines. add ('filter Description: '+ filterrec. DESC); memo1.lines. add ('----------------------------------------------'); For shadervaluerec in filterrec. values do begin memo1.lines. add ('parameter name: '+ shadervaluerec. name); memo1.lines. add ('parameter Description: '+ shadervaluerec. DESC); memo1.lines. add ('parameter type: '+ getenumname (typeinfo (tshadervaluetype), INTEGER (shadervaluerec. valuetype); If shadervaluerec. valuetype tshadervaluetype. vtbitmap then begin memo1.lines. add ('current value: '+ String (shadervaluerec. value); memo1.lines. add ('minimum: '+ String (shadervaluerec. min); memo1.lines. add ('default value: '+ String (shadervaluerec. default); memo1.lines. add ('maximum: '+ String (shadervaluerec. max); end; memo1.lines. add (emptystr); end;