Scenario 2, making Java2D fully available via string-based commands (Re: Minor thoughts (Re: [External] : Re: JEP draft: Prepare to Restrict The Use of JNI

[Rony G. Flatscher]

Consider the following ooRexx program that exploits the JRE (the Java classes available via the Java 
runtime environment, installed by OpenJDK) for Java2D:

    jdor=.bsf~new("org.oorexx.handlers.jdor.JavaDrawingHandler")   -- create a JDOR handler
         call BsfCommandHandler "add", "JDOR", jdor   -- add the JDOR handler to ooRexx
         address JDOR            -- set default environment to the JDOR command handler
             -- now we may use JDOR commands, executed by default by the JDOR command handler
         width =220              -- define width of image in pixels (there are 72 px to an inch)
         height=250              -- define height of image in pixels (there are 72 px to an inch)
         newImage width height   -- create new bitmap with currX=0, currY=0, width=220, height=250
         winShow                 -- show frame on screen
            -- draw two lines forming a big X
         drawLine (width-1) (height-1) -- from currX=0, currY=0
         color red               -- set the color to red (preregistered with nickname "RED")
         moveTo (width-1) 0      -- currX=219, currY=0
         position                -- query current position
         say "--> rc="pp(rc)     -- RC refers to the previous command's result: "219 0" (currX=219,
    currY=0)
         drawLine 0 (height-1)   -- from currX=219, currY=0
            -- draw a rectangle at the center of the bitmap
         len = 50                -- drawing a rectangle with each side being 50 px (a square)
         moveTo (width-len)/2 (height-len)/2 -- go to the center minus half of the square's side lengths
         color green             -- set color to green (preregistered with nickname "GREEN")
         fillRect len len        -- fill the square with the green color
         stroke str3 3           -- set line stroke to 3 points width, store it with nickname "STR3"
         color blue              -- set color to blue (preregistered with nickname "BLUE")
         drawRect len len        -- draw the frame with the blue color
            -- draw a string (text) at the lower half of the bitmap
         color somePurple 127 46 111   -- define a custom RGB color, store it with nickname "SOMEPURPLE"
         color                   -- query current color
         say "--> rc="pp(rc)     -- show result from command (a Java color object)
         say "    rc~toString:" pp(rc~toString) -- shows the RGB intensities of the current color
            -- draw three lines of centered strings at the bottom
         lineHeight = 15         -- default font size is 12px, add 3 px lead
         newY=height-40          -- draw the three strings at the bottom
         clrs=("somePurple", "blue", "gray")  -- define three different colors
         text=("Hello, Rexx world ...", "... from JDOR ...", "(a Rexx command handler)") -- array of
    3 strings
         do counter c i=0 to 30 by lineHeight   -- iterate over array of strings
            s=text[c]            -- fetch the string to draw from array
            stringBounds s       -- get the bounding box dimensions for this string
            parse var rc . . w . -- parse the width of the string's bounding box
            moveTo (width-w)/2 (newY+i)   -- calc x position to center this string, set y position
            color clrs[c]        -- fetch and use the color from the array
            drawString s         -- draw the string
         end
            -- save the current image
         saveImage "jdor_doc_sample.png"  -- save image to file "jdor_doc_sample.png"
         sleep 3.123             -- sleep for 3.123 seconds

         ::requires "BSF.CLS"    -- get ooRexx-Java bridge, contains JDOR Rexx command handler

To see its output in the command line window and the produced graphic cf. 
<https://wi.wu.ac.at/rgf/rexx/misc/jdor_doc.tmp/jdor_doc.html>. That is also at the same time (a 
temporary) location of the JDOR (Java2D for ooRexx) documentation.

---

This program runs on all versions of Java/OpenJDK unchanged.

With your currently intended warning all of a sudden all users of such programs/applications get 
frightened for no good reason!

---rony




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