Re: primitive graphics application

[steve donovan <steve.j.donovan@...>]

On Mon, May 4, 2009 at 7:15 AM, Dave Smead <smead@amplepower.com> wrote:
> My immediate interest is using Lua to access graphics primitives such as
> draw-line, draw-circle, draw-arc, etc

wxLua is probably a good fit.  A simple GUI program with graphics
primitives is really straightforward, very portable. (This was tested
using wxLua bundled with Lua For Windows)

steve d.

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-- draw.wlua (based on Minimal.wx.wlua from LfW)

-- Load the wxLua module, does nothing if running from wxLua,
wxLuaFreeze, or wxLuaEdit
require("wx")

frame = nil

-- paint event handler for the frame that's called by wxEVT_PAINT
function OnPaint(event)
    -- must always create a wxPaintDC in a wxEVT_PAINT handler
    local dc = wx.wxPaintDC(panel)
    -- call some drawing functions
    dc:DrawRectangle(10, 10, 300, 300);
    dc:DrawRoundedRectangle(20, 20, 280, 280, 20);
    dc:DrawEllipse(30, 30, 260, 260);
    dc:DrawText("A test string", 50, 150);
    -- the paint DC will be automatically destroyed by the garbage collector,
    -- however on Windows 9x/Me this may be too late (DC's are
precious resource)
    -- so delete it here
    dc:delete() -- ALWAYS delete() any wxDCs created when done
end

frame = wx.wxFrame( wx.NULL,            -- no parent for toplevel windows
                    wx.wxID_ANY,          -- don't need a wxWindow ID
                    "wxLua Draw Demo", -- caption on the frame
                    wx.wxDefaultPosition, -- let system place the frame
                    wx.wxSize(450, 450),  -- set the size of the frame
                    wx.wxDEFAULT_FRAME_STYLE ) -- use default frame styles

panel = wx.wxPanel(frame, wx.wxID_ANY)

-- connect the paint event handler function with the paint event
panel:Connect(wx.wxEVT_PAINT, OnPaint)

frame:Show(true)

wx.wxGetApp():MainLoop()

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