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--- copy_20key_20functionality_20with_20get_20and_20inkey [2018/04/16 10:46] – Added syntax highlighting richardrussell
+++ copy_20key_20functionality_20with_20get_20and_20inkey [2024/01/05 00:22] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
 =====Copy Key functionality with GET and INKEY=====
-//by Richard Russell, April 2008//\\ \\  BBC BASIC for Windows emulates the [[http://www.bbcbasic.co.uk/bbcwin/manual/bbcwin2.html#copyediting|Copy Key]] functionality provided on the BBC Microcomputer and other Acorn machines, but only at the Immediate Mode prompt or when user input is being requested using the INPUT statement; Copy Key editing is //not// available when the keyboard is read using GET or INKEY. The main reason for this limitation is that, in the absence of a dedicated Copy key, the Tab key is used instead to initiate the Copy operation. When GET or INKEY is used, the Tab key returns its normal ASCII value (9).\\ \\  Occasionally, especially when porting a program from an Acorn platform, it might be convenient for Copy Key editing to be available when using GET or INKEY. The code below provides this capability, by means of the user-defined function **FNinkeycopy**. This emulates the INKEY function (with a zero or positive parameter) but with the Tab key acting as the Copy key:
+//by Richard Russell, April 2008//\\
+//BBC BASIC for Windows// and //BBC BASIC for SDL 2.0// emulate the [[http://www.bbcbasic.co.uk/bbcwin/manual/bbcwin2.html#copyediting|Copy Key]] functionality provided on the BBC Microcomputer and other Acorn machines, but only at the Immediate Mode prompt or when user input is being requested using the INPUT statement; Copy Key editing is //not// available when the keyboard is read using GET or INKEY. The main reason for this limitation is that, in the absence of a dedicated Copy key, the Tab key is used instead to initiate the Copy operation. When GET or INKEY is used, the Tab key returns its normal ASCII value (9).\\ \\  Occasionally, especially when porting a program from an Acorn platform, it might be convenient for Copy Key editing to be available when using GET or INKEY. The code below provides this capability, by means of the user-defined function **FNinkeycopy**. This emulates the INKEY function (with a zero or positive parameter) but with the Tab key acting as the Copy key:
 <code bb4w>
-        DEF FNinkeycopy(T%)
+      DEF FNinkeycopy(T%)
-        LOCAL K%
+      LOCAL K%
-        PRIVATE copyX%, copyY%, copyF%
+      PRIVATE copyX%, copyY%, copyF%
-        IF copyF% PROCblob : PROCswap
+      IF copyF% PROCblob : PROCswap
-        REPEAT
+      REPEAT
-          K% = INKEY(T%)
+        K% = INKEY(T%)
-          CASE K% OF
+        CASE K% OF
-            WHEN 9:
+          WHEN 9:
-              IF copyF% THEN
+            IF copyF% THEN
-                K% = GET(POS, VPOS) : VDU 9
+              K% = GET(POS, VPOS) : VDU 9
-              ELSE
+            ELSE
-                copyX% = POS : copyY% = VPOS
+              copyX% = POS : copyY% = VPOS
-                copyF% = TRUE : PROCblob : K% = -1
+              copyF% = TRUE : PROCblob : K% = -1
-              ENDIF
+            ENDIF
-            WHEN 136,137,138,139:
+          WHEN 136,137,138,139:
-              IF copyF% VDU K% AND &7F : K% = -1
+            IF copyF% VDU K% AND &7F : K% = -1
-            WHEN 13, 155:
+          WHEN 13, 155:
-              IF copyF% THEN
+            IF copyF% THEN
-                IF K% = 155 K% = -1
+              IF K% = 155 K% = -1
-                copyF% = FALSE : PROCswap : PROCblob
+              copyF% = FALSE : PROCswap : PROCblob
-              ENDIF
+            ENDIF
-          ENDCASE
+        ENDCASE
-        UNTIL K%<>9
+      UNTIL K%<>9
-        IF copyF% PROCswap : PROCblob
+      IF copyF% PROCswap : PROCblob
-        = K%
+      = K%
-        DEF PROCswap
+      DEF PROCswap
-        LOCAL X%, Y%
+      LOCAL X%, Y%
-        X% = POS : Y% = VPOS
+      X% = POS : Y% = VPOS
-        SWAP X%, copyX% : SWAP Y%, copyY%
+      SWAP X%, copyX% : SWAP Y%, copyY%
-        PRINT TAB(X%,Y%);
+      PRINT TAB(X%,Y%);
-        ENDPROC
+      ENDPROC
-        DEF PROCblob
+      DEF PROCblob
-        LOCAL rc{}
+      LOCAL rc{}
-        DIM rc{l%,t%,r%,b%}
+      DIM rc{l%,t%,r%,b%}
-        rc.l% = @vdu%!48
+      rc.l% = @vdu%!48
-        rc.t% = @vdu%!52
+      rc.t% = @vdu%!52
-        rc.r% = rc.l% + @vdu%!216
+      rc.r% = rc.l% + @vdu%!216
-        rc.b% = rc.t% + @vdu%!220
+      rc.b% = rc.t% + @vdu%!220
-        SYS "InvertRect", @memhdc%, rc{}
+      SYS "InvertRect", @memhdc%, rc{}
-        SYS "InvalidateRect", @hwnd%, rc{}, 0
+      SYS "InvalidateRect", @hwnd%, rc{}, 0
-        ENDPROC
+      ENDPROC
+</code>
+In //BBC BASIC for SDL 2.0// replace **PROCblob** with the following code:
+<code bb4w>
+      DEF PROCblob
+      LOCAL rc{} : PRIVATE B%
+      IF B% = 0 SYS "SDL_ComposeCustomBlendMode", 8, 4, 1, 1, 2, 1 TO B%
+      DIM rc{x%,y%,w%,h%}
+      SYS "SDL_SetRenderDrawBlendMode", @memhdc%, B%
+      SYS "SDL_SetRenderDrawColor", @memhdc%, &FF, &FF, &FF, &FF
+      rc.x% = @vdu%!48  : rc.y% = @vdu%!52
+      rc.w% = @vdu%!216 : rc.h% = @vdu%!220
+      SYS "SDL_RenderFillRect", @memhdc%, rc{}
+      SYS "SDL_SetRenderDrawBlendMode", @memhdc%, 1
+      ENDPROC
 </code>
@@ Line 52: / Line 70: @@
 <code bb4w>
-        DEF FNgetcopy
+      DEF FNgetcopy
-        LOCAL K%
+      LOCAL K%
-        REPEAT
+      REPEAT
-          K% = FNinkeycopy(1)
+        K% = FNinkeycopy(1)
-        UNTIL K%<>-1
+      UNTIL K%<>-1
-        = K%
+      = K%
 </code>