; gdi+ ahk tutorial 4 written by tic (Tariq Porter)
; Requires Gdip.ahk either in your Lib folder as standard library or using #Include
;
; Tutorial to fill the screen with randomly hatched ellipses

#SingleInstance, Force
#NoEnv
SetBatchLines, -1

; Uncomment if Gdip.ahk is not in your standard library
;#Include, Gdip.ahk

; Start gdi+
If !pToken := Gdip_Startup()
{
	MsgBox, 48, gdiplus error!, Gdiplus failed to start. Please ensure you have gdiplus on your system
	ExitApp
}
OnExit, Exit

; Get the dimensions of the primary monitor
SysGet, MonitorPrimary, MonitorPrimary
SysGet, WA, MonitorWorkArea, %MonitorPrimary%
WAWidth := WARight-WALeft
WAHeight := WABottom-WATop

; Create a layered window (+E0x80000) that is always on top (+AlwaysOnTop), has no taskbar entry or caption
Gui, 1: -Caption +E0x80000 +LastFound +OwnDialogs +Owner +AlwaysOnTop

; Show the window
Gui, 1: Show, NA

; Get a handle to this window we have created in order to update it later
hwnd1 := WinExist()

; Create a gdi bitmap with width and height of the work area
hbm := CreateDIBSection(WAWidth, WAHeight)

; Get a device context compatible with the screen
hdc := CreateCompatibleDC()

; Select the bitmap into the device context
obm := SelectObject(hdc, hbm)

; Get a pointer to the graphics of the bitmap, for use with drawing functions
G := Gdip_GraphicsFromHDC(hdc)

; Set the smoothing mode to antialias = 4 to make shapes appear smother (only used for vector drawing and filling)
Gdip_SetSmoothingMode(G, 4)

; Set a timer to draw a new ellipse every 200ms
SetTimer, DrawCircle, 200
Return

;#######################################################################

DrawCircle:
; Get a random colour for the background and foreground of hatch style used to fill the ellipse,
; as well as random brush style, x and y coordinates and width/height
; 0 = 0x00000000 and 4294967295 = 0xffffffff as the latest version of ahk has broken Random function that dont use floating point values
Random, RandBackColour, 0, 4294967295.0
Random, RandForeColour, 0, 4294967295.0
Random, RandBrush, 0, 53
Random, RandElipseWidth, 1, 200
Random, RandElipseHeight, 1, 200
Random, RandElipsexPos, %WALeft%, % WAWidth-RandElipseWidth			;%
Random, RandElipseyPos, %WATop%, % WAHeight-RandElipseHeight		;%

; Create the random brush
pBrush := Gdip_BrushCreateHatch(RandBackColour, RandForeColour, RandBrush)

; Fill the graphics of the bitmap with an ellipse using the brush created
Gdip_FillEllipse(G, pBrush, RandElipsexPos, RandElipseyPos, RandElipseWidth, RandElipseHeight)

; Update the specified window
UpdateLayeredWindow(hwnd1, hdc, WALeft, WATop, WAWidth, WAHeight)

; Delete the brush as it is no longer needed and wastes memory
Gdip_DeleteBrush(pBrush)
Return

;#######################################################################

Exit:
; Select the object back into the hdc
SelectObject(hdc, obm)

; Now the bitmap may be deleted
DeleteObject(hbm)

; Also the device context related to the bitmap may be deleted
DeleteDC(hdc)

; The graphics may now be deleted
Gdip_DeleteGraphics(G)

; ...and gdi+ may now be shutdown
Gdip_Shutdown(pToken)
ExitApp
Return