Xojo: THE Canvas reference book

Program the Canvas Control with Xojo Desktop
Program the Canvas Control with Xojo Desktop

I Wish I Knew How To… Program the Canvas Control with Xojo Desktop is the latest book of Eugene Dakin in his excellent I Wish I Knew How To… series.

If you ever wondered how stuff is done with the canvas control in Xojo, this is the book you need to have on your virtual shelf. In his well known swift (no pun intended) style, Eugene has written the reference manual for you. Alwaysbusy’s Corner did some humble contributions to the more advanced topics.

For the novice Xojo user, you quickly can get started and learn about the basics of graphics. Step by step you learn more and more when you move through the more advanced topics. This 400 page volume covers a lot of interesting chapters and includes a lot of useful examples with source code:

Topics included in the book:

Text
Chart Fundamentals
Objects
2D Objects
Graphics
Blurring
Cropping
Gaussian Blur
Building basic controls
Animation
and there are two games with step-by-step code explanations to help you build your own.

So head over to Eugene’s Personal Website and get your copy. Also check out his other books in the series on topics like SQLite, XML, PostgreSQL, Office etc…

Click here to Donation if you like my work

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QuiQRun! Localization

QuiQRun! Skin Italia
Skinning QuiQRun!

Hi all,

I’m looking for people who can translate about 150 terms and some short sentences for my new app QuiQRun! If you can help me, send me a mail to alain.bailleul@pandora.be.

I already have English, Dutch, Italian, French, German, Spanish and Portuguese.

What can I offer?

1. The full version of QuiQRun!
2. A skin in QuiQRun! with your favorite colors
3. Full credit in the apps credits screen
4. Eternal gratitude!

How do I use it in B4A?
The translations are stored in a language file, eg. en-us.lng.

They are stored in a predefined format:

{0000};Scanned
{0001};Scan
{0002};Create
{0003};Setting new skin, one moment...
{0004};Tap to get more info!
{0005};This QRCode is expired!
...

In Basic4Android, It checks if it has a translation, if not it uses the default you put in the GetString function. Here is the snippet I use:

Sub Process_Globals
    Public LangStrings As Map
    Public BOM As Int = 65279 ' Byte Order Mark for Windows UTF-8 files
End Sub

Sub Activity_Create(FirstTime As Boolean)
    Dim R As Reflector
    R.Target = R.RunStaticMethod("java.util.Locale", "getDefault", Null, Null)
    Dim tmpLang As String = R.RunMethod("getLanguage")
    Select Case tmpLang
        Case "nl"
            LoadLanguageFile("nl-be.LNG")
        Case "fr"
            LoadLanguageFile("fr-fr.LNG")           
        Case "it"
            LoadLanguageFile("it-it.LNG")
        Case "es"
            LoadLanguageFile("es-es.LNG")
        Case "de"
            LoadLanguageFile("de-de.LNG")
        Case Else
            LoadLanguageFile("en-us.LNG")
    End Select

    ' using it:
    ToastMessageShow(GetString("{0003}","Setting new skin, one moment..."), true)
End Sub

Public Sub LoadLanguageFile(setLanguageFile as String)
    LangStrings.Initialize
    
    If File.Exists(File.DirAssets, setLanguageFile) Then
        Dim txtR As TextReader
        txtR.Initialize(File.OpenInput(File.DirAssets, setLanguageFile))
        Dim line As String
        line = txtR.ReadLine
        Do While line  Null
            line = line.Replace(Chr(BOM), "")
            LangStrings.Put(line.SubString2(0,6), line.SubString(7))
            line = txtR.ReadLine
        Loop
        txtR.Close
    End If   
    
End Sub

Public Sub GetString(iCode As String, iDefault As String) As String
    If LangStrings.ContainsKey(iCode) Then
        Return LangStrings.Get(iCode)
    Else
        Return iDefault
    End If
End Sub

Thanks!

Alwaysbusy

QuiQRun! A glimpse…

QuiQRun
I’m currently working on my new Android app called QuiQRun and this is the first time it is presented to the public. It is currently in the testing phase so it won’t be long until I will release it to Google Play.

What is QuiQRun?

QuiQRun consists of two main parts:

1. The White side: Save – Share – Scan QR Codes

• Scan QR Codes and barcodes with our fast build in scanner
• Decrypt codes created with QuiQRun Security and read codes generated by other apps
• A human readable summary and the raw QR data
• Save codes for later use. All codes are organized in a nice list for easy retrieval.
• Share your QR Code on Facebook, Twitter, Email, Dropbox and many more…
• Use the QR Code immediately on your smartphone

2. The Black side: Make – Share – Protect QR Codes

• Make QR Codes for Websites, Wifi, Contacts, locations, coupons and many more…
• Protect your QR Code with QuiQRun Security
– Encryption
– Prevent saving the QR Code
– Password or PIN protect
– Set an expiration date
• Share your QR code on Facebook, Twitter, Email, Dropbox and many more…
• Use the QR Code immediately on your smartphone

And here are the first screenshots!

QuiQRun
QuiQrun on Android

QuiQRun is written in Basic4Android. If you are a licensed user of B4A you can download an exclusieve preview version from the B4A ‘Test my App!’ forum! I would definitely appreciate the feedback 🙂

More information and screenshots can be found at QuiQRun

The coming weeks I’ll keep you up to date. Follow me on Twitter: QuiQRun

Alwaysbusy

Basic4Android: A first look at ABPlay, a game engine library

ABPlay Screenshot
ABPlay Screenshot

It has been a while since I’ve written a new article on this blog because it have been busy months both at work and in my personal life. One of the things I wanted to do was writing an easy to use Game Engine for B4A. I have written the ABPhysics engine in the past and recently Informatix pointed out I had started another engine (ABGameEngine) before that. Development on ABGameEngine was stopped early for several reasons: time was one of them, but also because several other developers were working on an engine themselves. It seemed a little bit pointless to continue.

However, the other engines were not further developed either. Until recently Erel came up with the GameView. This is an excellent View that will cover the needs of a lot of beginning programmers. I definitely would like to urge starting game developers to take a look at this. Registered users of B4A can download the GameView lib from here.

But still, I wanted something more. I looked at ABgameEngine again, as it had some great ideas like layers, animated sprites, gamepads etc. But it was also very old code and not written very well. And it crashed all the time 🙂

I decided to restart from scratch a couple of weeks ago. Some weekends and evenings later ABPlay was born! And with a lot of goodies!

Here is a small demo video of what I got so far. it demonstrates the following:

1. Layers
     (Layer 1) the moving background with the Odies as animated sprites
     (Layer 2) the black foreground layer with a weird dancing creature that passes now and then
2. Animated sprites, not bound to a layer
     (our hero Garfield is back!)
3. A sprite can have different animations.
     (like one for standing, one for walking, one for fighting, etc)
4. A sprite can have different predefined 'Walks'
     (A walk can be build like you would build a path. It's a sequence of lines, bezier curves, wait periods etc. It's like a simple flash movie)
5. Gamepad controls
     (the 'joystick' pad on the left)
     (the 'action' pad on the right)
     (the 'direction' pad as an alternative to the joystick, not shown in this video)
6. In the demo I cannot demonstrate it with a mouse, but it is completely multi touch
     (You can control Garfield AND press the Action button X AND do a swipe anywhere at the same time)

But let’s have a look (beware this is running on the Emulator. On a real device it is much smoother):

I’m actually very pleased with the result. The graphics and handling is very smooth.
Above all, it’s still very easy to program. Here is the whole code for the demo app:

#Region  Project Attributes
	#ApplicationLabel: ABPlayTest
	#VersionCode: 1
	#VersionName:
	'SupportedOrientations possible values: unspecified, landscape or portrait.
	#SupportedOrientations: landscape
	#CanInstallToExternalStorage: False
#End Region

#Region  Activity Attributes
	#FullScreen: true
	#IncludeTitle: false
#End Region

Sub Process_Globals

End Sub

Sub Globals
	Dim myPlay As ABPlay
	' the panel that will hold the ABPlay
	Dim myPanel As Panel

	' a background and foregroud layer
	Dim bgLayer As ABLayer
	Dim fgLayer As ABLayer

	' some colors to show the multi touch points in the demo
	Dim myColors() As Int = Array As Int(Colors.Red, Colors.Green, Colors.Blue, Colors.Cyan, Colors.Yellow, Colors.Gray, Colors.White, Colors.Magenta, Colors.LightGray, Colors.DarkGray)

	' our hero
	Dim Hero As ABSprite
	' our enemies
	Dim Enemies As List

	' param to set the set the speed
	Dim Speed As Float = 0.2

	' some variables to hold the current state of the hero
	Dim currentAction As String
	Dim currentDirection As String
	Dim currentIsStanding As Boolean
End Sub

Sub Activity_Create(FirstTime As Boolean)
	' initialize ABPlay with myPanel
	myPanel.Initialize("")
	Activity.AddView(myPanel, 0,0,100%x,100%y)
	myPlay.Initialize(myPanel, "myPlay")

	'////////////// BEGIN loading sprite sequences
	' Load Sprite Sequences
	myPlay.LoadSpriteSequence("GarStandingLeft",LoadBitmap(File.DirAssets, "garleftstill.png"),6, 1, 1000)
	myPlay.LoadSpriteSequence("GarStandingLeft",LoadBitmap(File.DirAssets, "garleftstill.png"),6, 1, 1000)
	myPlay.LoadSpriteSequence("GarStandingRight",LoadBitmap(File.DirAssets, "garrightstill.png"),6, 1, 1000)
	myPlay.LoadSpriteSequence("GarWalkingLeft",LoadBitmap(File.DirAssets, "garleft.png"),8, 1, 1000)
	myPlay.LoadSpriteSequence("GarWalkingRight",LoadBitmap(File.DirAssets, "garright.png"),8, 1, 1000)
	myPlay.LoadSpriteSequence("GarStandingLeftFight",LoadBitmap(File.DirAssets, "garleftstillfight.png"),2, 1, 250)
	myPlay.LoadSpriteSequence("GarStandingRightFight",LoadBitmap(File.DirAssets, "garrightstillfight.png"),2, 1, 250)
	myPlay.LoadSpriteSequence("GarWalkingLeftFight",LoadBitmap(File.DirAssets, "garleftfight.png"),7, 1, 1000)
	myPlay.LoadSpriteSequence("GarWalkingRightFight",LoadBitmap(File.DirAssets, "garrightfight.png"),7, 1, 1000)
	' and the ones for Odie
	myPlay.LoadSpriteSequence("OdieStandingLeft", LoadBitmap(File.DirAssets, "odieleftstill.png"),7,1,Rnd(800,1200))
	myPlay.LoadSpriteSequence("OdieStandingRight", LoadBitmap(File.DirAssets, "odierightstill.png"),7,1,Rnd(800,1200))
	myPlay.LoadSpriteSequence("OdieWalkingLeft", LoadBitmap(File.DirAssets, "odieleft.png"),5,1,Rnd(800,1200))
	myPlay.LoadSpriteSequence("OdieWalkingRight", LoadBitmap(File.DirAssets, "odieright.png"),5,1,Rnd(800,1200))
	' and the one for the creature
	myPlay.LoadSpriteSequence("CreaturePassToRight", LoadBitmap(File.DirAssets, "creature.png"), 3, 4, 1200)
	'////////////// END loading sprite sequences

	'////////////// BEGIN building the Hero Garfield
	' initialize the hero
	Hero.Initialize("Hero", 50%x, 50%y)
	' add sprite sequences
	Hero.AddSpriteSequence("GarStandingLeft")
	Hero.AddSpriteSequence("GarStandingRight")
	Hero.AddSpriteSequence("GarWalkingLeft")
	Hero.AddSpriteSequence("GarWalkingRight")
	Hero.AddSpriteSequence("GarStandingLeftFight")
	Hero.AddSpriteSequence("GarStandingRightFight")
	Hero.AddSpriteSequence("GarWalkingLeftFight")
	Hero.AddSpriteSequence("GarWalkingRightFight")
	Hero.StartSpriteSequence("GarStandingLeft", True)
	currentDirection="LEFT"
	'//////////////  END building the Hero Garfield

	'////////////// BEGIN building the background layer with Odies
	' initalize a background layer
	bgLayer.Initialize("background", 0,0)
	bgLayer.SetBackground(LoadBitmap(File.DirAssets, "bga.jpg"), 1.0)
	myPlay.AddLayer(bgLayer)

	' initialize some enemies
	Enemies.Initialize
	Dim a As Int
	For a = 1 To 10
		Dim Odie As ABSprite

		' initialize an Odie with some animation sequences
		Odie.Initialize("Odie" & a, Rnd(10%x,90%x), Rnd(10%y, 90%y))
		' add multiple sprite sequences
		Odie.AddSpriteSequences(Array As String("OdieStandingLeft","OdieStandingRight","OdieWalkingLeft","OdieWalkingRight"))

		' create a random walk to the right
		Dim WalkRight As ABSpriteWalk
		WalkRight.Initialize("ToTheRight", True)
		Dim newX As Int = Odie.x+Rnd(20%x, 80%x)
		WalkRight.AddLine("OdieWalkingRight",Odie.x, Odie.y, newX, Odie.y, Rnd(90,100))
		WalkRight.AddWait("OdieStandingRight",newX, Odie.y, Rnd(10,50))
		WalkRight.AddLine("OdieWalkingLeft",newX, Odie.y, Odie.x, Odie.y, Rnd(90,100))
		WalkRight.AddWait("OdieStandingLeft",Odie.x, Odie.y, Rnd(10,50))
		Odie.AddWalk(WalkRight)

		' create a random walk to the left
		Dim WalkLeft As ABSpriteWalk
		WalkLeft.Initialize("ToTheLeft", True)
		Dim newX As Int = Odie.x-Rnd(20%x, 80%x)
		WalkLeft.AddLine("OdieWalkingLeft",Odie.x, Odie.y, newX, Odie.y , Rnd(90,100))
		WalkLeft.AddWait("OdieStandingLeft",newX, Odie.y, Rnd(10,50))
		WalkLeft.AddLine("OdieWalkingRight",newX, Odie.y, Odie.x, Odie.y, Rnd(90,100))
		WalkLeft.AddWait("OdieStandingRight",Odie.x, Odie.y, Rnd(10,50))
		Odie.AddWalk(WalkLeft)

		' pick random a walk, left or right
		Dim GoLeft As Int = Rnd(0,2)
		If GoLeft = 0 Then
			Odie.StartWalk("ToTheRight")
		Else
			Odie.StartWalk("ToTheLeft")
		End If
		bgLayer.AddSprite(Odie)
	Next
	'////////////// END building the background layer with Odies

	'////////////// BEGIN building the foreground layer with creature
	' initalize a foreground layer
	Dim fgLayer As ABLayer
	fgLayer.Initialize("foreground", 0,0)
	fgLayer.SetBackground(LoadBitmap(File.DirAssets, "fga.png"), 100%y/400)
	myPlay.AddLayer(fgLayer)

	' and a weird creature...
	Dim creature As ABSprite
	creature.Initialize("creature", -100%x, 100%y-240)
	creature.AddSpriteSequence("CreaturePassToRight")
	' with a walk
	Dim pass As ABSpriteWalk
	pass.Initialize("DanseToTheRight", True)
	pass.AddLine("DansingRight",creature.x, creature.y, 200%x, creature.y, 300)
	creature.AddWalk(pass)
	' and start the walk
	creature.StartWalk("DanseToTheRight")
	' add the creature to the foreground layer
	fgLayer.AddSprite(creature)
	'////////////// END building the foreground layer with creature

	'////////////// BEGIN Add game pads
	' initialize and start a Joystick Gamepad
	myPlay.InitializeJoystickPad(18, 100%y-210, 192, 192 , LoadBitmap(File.DirAssets, "joystick_bg.png"),LoadBitmap(File.DirAssets, "joystick.png"))
	myPlay.ShowJoystickPad(True)	

	' initialize and start a Action Gamepad
	myPlay.InitializeActionPad(100%x-210, 100%y-210, 192, 192 , LoadBitmap(File.DirAssets, "action_active.png"),LoadBitmap(File.DirAssets, "action_inactive.png"),LoadBitmap(File.DirAssets, "action_mask.png"),True, False, True, False)
	myPlay.ShowActionPad(True)
	'////////////// END Add game pads
End Sub

Sub Activity_Resume

End Sub

Sub Activity_Pause (UserClosed As Boolean)
	' NEEDED FOR THE MOMENT TO CATCH THE HOME KEY, RESUME/PAUSE NOT YET SUPPORTED!
	myPlay.StopAndRecycle
	Activity.Finish
End Sub

Sub Activity_KeyPress (KeyCode As Int) As Boolean 'Return True to consume the event
	Select Case KeyCode
		Case KeyCodes.KEYCODE_BACK
			' NEEDED: stop the drawing thread and recycle stuff
			myPlay.StopAndRecycle
			Activity.Finish
			Return True
		Case KeyCodes.KEYCODE_HOME
			Return True
	End Select
End Sub

Sub myPlay_Draw(c As Canvas, State As ABState)
	' the actual drawing, do NOT set a debug stop in here!

	'////////////// BEGIN Calculation stuff
	' calculate hero stuff depending on what buttons we pressed on the gamepad
	currentAction = ""
	If State.UsingActionPad Then
		' go into fight state
		If State.ACTION_X Then
			currentAction = "X"
		End If
		' go back to center
		If State.ACTION_Y Then
			Hero.SetPostition(50%x,50%y)
		End If
	End If

	Dim XMovement As Int
	Dim YMovement As Int
	If State.UsingJoystickPad Then
		XMovement = State.JOYSTICK_X*Speed
		YMovement = State.JOYSTICK_Y*Speed
		' update the hero's position and direction
		If XMovement<0 Then
			currentDirection = "LEFT"
		Else
			currentDirection = "RIGHT"
		End If
		Hero.SetPostition(Hero.x+XMovement, Hero.y+YMovement)
		currentIsStanding = False
	Else
		currentIsStanding = True
	End If

	' set the animation type
	Select Case currentDirection
		Case "LEFT"
			Select Case currentAction
				Case "X"
					If currentIsStanding Then
						Hero.StartSpriteSequence("GarStandingLeftFight", False)
					Else
						Hero.StartSpriteSequence("GarWalkingLeftFight", False)
					End If
				Case Else
					If currentIsStanding Then
						Hero.StartSpriteSequence("GarStandingLeft", False)
					Else
						Hero.StartSpriteSequence("GarWalkingLeft", False)
					End If
			End Select
		Case "RIGHT"
			Select Case currentAction
				Case "X"
					If currentIsStanding Then
						Hero.StartSpriteSequence("GarStandingRightFight", False)
					Else
						Hero.StartSpriteSequence("GarWalkingRightFight", False)
					End If
				Case Else
					If currentIsStanding Then
						Hero.StartSpriteSequence("GarStandingRight", False)
					Else
						Hero.StartSpriteSequence("GarWalkingRight", False)
					End If
			End Select
	End Select	

	' update the hero animation
	Hero.Update

	' move our backgrounds, does not make sense but shows the possibilities
	Dim newX, newY As Int
	Dim newMovementX, newMovementY As Int
	newMovementX=Min(Abs(XMovement),1)
	newMovementY=Min(Abs(YMovement),1)
	If currentIsStanding = False Then
		If currentDirection = "LEFT" Then
			newX = bgLayer.ViewX
			newY = bgLayer.ViewY
			If newX-newMovementX >= 0 Then
				newX = newX-newMovementX
			End If
			If newY-newMovementY >= 0 Then
				newY = newY-newMovementY
			End If
			bgLayer.SetLayerPostion(newX, newY)
		Else
			newX = bgLayer.ViewX
			newY = bgLayer.ViewY
			If newX+newMovementX <= bgLayer.OuterWidth - myPlay.Width Then
				newX = newX+newMovementX
			End If
			If newY+newMovementY <= bgLayer.OuterHeight - myPlay.Height Then
				newY = newY+newMovementY
			End If
			bgLayer.SetLayerPostion(newX, newY)
		End If
	End If

	'////////////// END Calculation stuff

	'////////////// BEGIN Drawing stuff
	'ok, all the calulations are done, let's draw!

	' draw the background layer with all its sprites on it and advance all sprite animations and walks
	myPlay.DrawLayer("background", c)

	Dim a As Int
	' draw the multitouch points that are not on the gamepad, no action here but just to show the possibilities
	For a = 0 To State.touchPoints.Size - 1
		Dim tmpP As ABTouchPoint
		tmpP = State.touchPoints.GetValueAt(a)
		c.DrawCircle(tmpP.X, tmpP.Y, 50dip, myColors(tmpP.id), True, 1dip)
	Next

	' draw the hero
	Hero.Draw(c)

	' draw the foreground layer with all its sprites on it and advance all sprite animations and walks
	myPlay.DrawLayer("foreground", c)
	'////////////// END Drawing stuff

	' NEEDED: very last line of the Draw event. Let ABPlay know it may process touches again!
	myPlay.DrawDone()
End Sub

I’m not there yet, but it’s a good start. It needs a lot more testing and a lot of new features.

Until next time!
Alwaysbusy

Click here to Donation if you like my work

Basic4Android: Using the new 3D Camera in ABExtDrawing 1.1

I’ve added the Camera object to the ABExtDrawing library for Basic4Android. This object must not be confused with the hardware camera. There are other libraries available for that. The new version 1.1 of the library can be downloaded from the B4X website.

The camera I’m talking about is a nice feature you can use to do 3D effects on the canvas without using OpenGL. The picture above is just a noral B4A canvas where we did some rotations and translations on. It simulates a scrolling list where the listitems rotate around their axe.

Additional, I shows other features of the ABExtDrawing library to do some lighting effects.

Let me show you how this is done in B4A.

We create a new type item3D. This will hold one item in the list.

Sub Process_Globals
	Type item3D (bmp As Bitmap, Top As Int, Left As Int, Width As Int, Height As Int)
End Sub

We also have to declare some variables. Note our mCamera variable which will do the 3D conversions and some constants for our lighting effects. On a Paint object we can set color filters which will affect the color values of what we draw with that Paint object. SetLightingColorFilter takes care of that. A LightingColorFilter takes two colors that are used to modify the colors that we are drawing. The first color will be multiplied with the colors we draw, while the second one will be added to the colors we draw. The multiplication will darken the color and adding will make it brighter so we can use this class to model both shadows and highlights. It would have been even better if instead of adding it would have implemented the screen blend mode, but add works OK.

To actually calculate the light we’ll use a simplified version of Phong lighting.

Sub Globals
	'These global variables will be redeclared each time the activity is created.
	'These variables can only be accessed from this module.
	Dim items As List
	Dim HalfHeight As Float

	Dim SCALE_DOWN_FACTOR As Float: SCALE_DOWN_FACTOR = 0.15
	Dim DEGREES_PER_SCREEN As Int: DEGREES_PER_SCREEN = 270

	' Ambient light intensity
    Dim AMBIENT_LIGHT As Int: AMBIENT_LIGHT = 55
    ' Diffuse light intensity
    Dim DIFFUSE_LIGHT As Int: DIFFUSE_LIGHT = 200
    ' Specular light intensity
    Dim SPECULAR_LIGHT As Float: SPECULAR_LIGHT = 70
    ' Shininess constant
    Dim SHININESS As Float: SHININESS = 200
    ' The Max intensity of the light
    Dim MAX_INTENSITY As Int: MAX_INTENSITY = 0xFF

	Dim CurrentRotation As Int
	Dim CurrentTop As Int
	Dim MyCanvas As Canvas

	Dim ScreenTop As Int: ScreenTop = 1
	Dim Panel1 As Panel

	Dim ExDraw As ABExtDrawing
	Dim mCamera As ABCamera
	Dim mMatrix As ABMatrix
	Dim mPaint As ABPaint

	Dim PI As Double: PI= 3.141592653589793238462643383279502884197

	Dim ClearRect As Rect

	Dim CurrY As Int
End Sub

In the Activity_Create sub we initialize mCamera and the other variables like mPaint which we will also need for our lighting. Also our pictures are preloaded.

Sub Activity_Create(FirstTime As Boolean)
	Activity.LoadLayout("1")

	MyCanvas.Initialize(Panel1)

	HalfHeight = Activity.Height / 2

	Dim backbmp As Bitmap
	backbmp.Initialize(File.DirAssets, "background.png")
	Dim backbmp2 As Bitmap
	backbmp2.Initialize(File.DirAssets, "background2.png")
	Dim backbmp3 As Bitmap
	backbmp3.Initialize(File.DirAssets, "background3.png")

	Dim conbmp As Bitmap
	conbmp.Initialize(File.DirAssets, "contact_image.png")
	Dim conbmp2 As Bitmap
	conbmp2.Initialize(File.DirAssets, "contact_image2.png")
	Dim conbmp3 As Bitmap
	conbmp3.Initialize(File.DirAssets, "contact_image3.png")

	items.Initialize
	Dim i As Int
	Dim random As Int
	For i = 0 To 19
		random = Rnd(0,3)
		If random = 0 Then
			items.Add(CreateNewItem(backbmp, conbmp, "Colleague " & i, "Name of colleague " & i, 25, i*175, Activity.Width - 50, 120))
		Else
			If random = 1 Then
				items.Add(CreateNewItem(backbmp2, conbmp2, "Friend " & i, "Name of friend " & i, 25, i*175, Activity.Width - 50, 120))
			Else
				items.Add(CreateNewItem(backbmp3, conbmp3, "Client " & i, "Name of the client " & i, 25, i*175, Activity.Width - 50, 120))
			End If
		End If
	Next

	CurrentRotation = -(DEGREES_PER_SCREEN * ScreenTop) / Activity.Height

	ClearRect.Initialize(0,0,Activity.Width, Activity.Height)

	mCamera.Initialize
	mMatrix.Initialize
	mPaint.Initialize
	mPaint.SetAntiAlias(True)
    mPaint.SetFilterBitmap(True)

	DrawMe
End Sub

The sub CreateNewItem() is used to make one list item. Default B4A canvas drawing functions are used to show how well they work together with the ABExtDrawing functions.

Sub CreateNewItem(Background As Bitmap, icon As Bitmap, Subj As String, desc As String, Left As Int, Top As Int, Width As Int, Height As Int) As item3D
	Dim item As item3D
	Dim c As Canvas
	item.Initialize
	item.bmp.InitializeMutable(Width, Height)

	c.Initialize2(item.bmp)

	' background
	Dim dstR As Rect
	dstR.Initialize(0,0,Width,Height)
	c.DrawBitmap(Background,Null, dstR)

	' draw Icon
	dstR.Initialize(15,15, icon.Width, icon.Height)
	c.DrawBitmap(icon, Null, dstR)

	c.DrawText(Subj, 100, 30,Typeface.DEFAULT_BOLD,16, Colors.White,"LEFT")
	c.DrawText(desc, 100, 60, Typeface.DEFAULT,16, Colors.White,"LEFT")

	item.Top = Top
	item.Left = Left
	item.Width = Width
	item.Height = Height
	Return item
End Sub

In the drawItem() sub all calculations are done for one item in the list. Each item will be a block that will rotate around its X-axis and look like it is rolling on the ground when the list stars to scroll. Each block will be as wide as the item normally is and the depth will be the same as the height. We’ll use the same bitmap for all the sides.

So what do we need to do to achieve this effect? In order to draw the blocks we need to draw the bitmap two times (since we will almost always see two sides of the block). We also need to have some kind of rotation variable to keep track of the main rotation. Since the blocks should rotate when the user scrolls the list and the blocks should have the same rotation (so that they all face up at the same time, see further).

Sub DrawItem(item As item3D)
	Dim CenterX As Float
	Dim CenterY As Float

	' get centerX AND centerY
	CenterX = item.Width / 2
	CenterY = item.Height / 2

    ' get scale
    Dim distFromCenter As Float
	distFromCenter = (item.Top + CenterY - HalfHeight) / HalfHeight
	Dim scale As Float
	scale = (1 - SCALE_DOWN_FACTOR * (1 - Cos(distFromCenter)))

    ' get rotation
    Dim RotationX As Float
	RotationX = CurrentRotation - 20 * distFromCenter
    RotationX = RotationX Mod 90
    If (RotationX < 0) Then
        RotationX = RotationX + 90
    End If	

    ' draw it
    If (RotationX < 45) Then
		drawFace(item, CenterX, CenterY, scale, RotationX - 90)
        drawFace(item, CenterX, CenterY, scale, RotationX)

    Else
        drawFace(item, CenterX, CenterY, scale, RotationX)
        drawFace(item, CenterX, CenterY, scale, RotationX - 90)
    End If
End Sub

Finally, DrawFace is called and this is where the magic happens. Worth noting is that the code that will draw one face of the block is the same, it just depends on the rotation, so it’s extracted to a method. To draw a complete block we then simply draw two faces 90 degrees apart at the same place.

To draw a face we first translate the camera so that the face will be drawn closer to us. Then we rotate it and after that we translate it back so we don’t scale it. Keep in mind that the calls to the camera, just like the rotate, translate and scale methods on Canvas, needs to be written in reversed order, so to speak. In the code below, it is the last line that translates the face towards us, then we rotate it, and finally, with the first line, we translate it back.

mCamera.translate(0, 0, centerY);
mCamera.rotateX(rotation);
mCamera.translate(0, 0, -centerY);

The rest of drawFace is not that hard. It gets the matrix from the camera, pre and post translates the matrix and then draws the bitmap with the matrix.

This code will draw each item as if placed in the origin in 3D space and then we move the items to the correct place on the screen using pre and post translate on the matrix. This moves what we draw in 2D space without changing the perspective. We could apply the translation in X and Y on the camera instead, then the translation would be in 3D space and it would affect the perspective. We’re not doing that here because I want the appearance of a larger field of view than the fixed field of view of the camera. Instead, we fake it by slightly rotating and scaling the items depending on the distance from center of the screen.

We calculate the light and create a LightingColorFilter that we can set to our Paint object.

Sub drawFace(item As item3D, CenterX As Float, CenterY As Float, scale As Float, RotationX As Float)
	' save the camera state
    mCamera.save

    ' translate AND Then rotate the camera
    mCamera.translate(0, 0, CenterY)
    mCamera.rotateX(RotationX)
	mCamera.translate(0, 0, -CenterY)

    ' get the matrix from the camera AND Then restore the camera
    mCamera.getMatrix(mMatrix)
    mCamera.restore()

    ' translate AND scale the matrix
    mMatrix.preTranslate(-CenterX, -CenterY)
    mMatrix.postScale(scale, scale)
    mMatrix.postTranslate(item.left + CenterX, item.top + CenterY)

    ' set the light
	Dim cosRotation As Double
	cosRotation = Cos(PI * RotationX / 180)
    Dim intensity As Int
	intensity = AMBIENT_LIGHT + (DIFFUSE_LIGHT * cosRotation)
    Dim highlightIntensity As Int
	highlightIntensity = (SPECULAR_LIGHT * Power(cosRotation,SHININESS))
    If (intensity > MAX_INTENSITY) Then
        intensity = MAX_INTENSITY
    End If
    If (highlightIntensity > MAX_INTENSITY) Then
        highlightIntensity = MAX_INTENSITY
    End If
    Dim light As Int
	light = Colors.rgb(intensity, intensity, intensity)
    Dim highlight As Int
	highlight = Colors.rgb(highlightIntensity, highlightIntensity, highlightIntensity)
    mPaint.SetLightingColorFilter(light, highlight)   

    ' draw the Bitmap
    ExDraw.drawBitmap4(MyCanvas, item.bmp,  mMatrix, mPaint)
End Sub

The DrawMe() sub is the overall function to draw all the items.

Sub DrawMe()
	Dim i As Int
	ExDraw.save2(MyCanvas, ExDraw.MATRIX_SAVE_FLAG)
	MyCanvas.DrawRect(ClearRect, Colors.Black, True, 1dip)
	'MyCanvas.DrawBitmap(FormBack, Null, formR)
	For i = 0 To items.Size - 1
		DrawItem(items.Get(i))
	Next
	ExDraw.restore(MyCanvas)

	Panel1.Invalidate
End Sub

And in the Panel1_Touch sub we’ll animate our list. Note that it is here that we make sure all boxes face the same. This is done by the lines:

ScreenTop = ScreenTop + DeltaY
CurrentRotation = -(DEGREES_PER_SCREEN * ScreenTop) / Activity.Height

Doing like this will make the blocks rotate DEGREES_PER_SCREEN degrees when the user scrolls the list an entire screen no matter the pixel-height of the screen.

Here is the full sub:

Sub Panel1_Touch (Action As Int, X As Float, Y As Float) As Boolean 'Return True to consume the event
	Dim DeltaY As Int
	Select Action
        Case Activity.ACTION_DOWN
			CurrY = Y
            'Log("down")
        Case Activity.ACTION_MOVE
			DeltaY = Y - CurrY
			CurrY = Y
			Dim i As Int
			Dim it As item3D
			For i = 0 To items.Size - 1
				it = items.Get(i)
				it.Top = it.Top + DeltaY
				items.Set(i, it)
			Next

			ScreenTop = ScreenTop + DeltaY
			CurrentRotation = -(DEGREES_PER_SCREEN * ScreenTop) / Activity.Height

			DrawMe
            'Log("move")
        Case Activity.ACTION_UP
            'Log("up")
    End Select
    Return True
End Sub

So this concludes this tutorial. You can download the project from http://www.gorgeousapps.com/AB3DCamera.zip

Note that at the first run, it may not work very smooth on some devices. But after some time it goes very well.

Have fun programming and until next time!

Click here to Donation if you like my work

Basic4Android: new library ABExtDrawing

ABExtDrawing is a library I wrote to access more from the Android Drawing classes in B4A. It extends the B4A canvas so you can also use all Paint, Matrix, Region, ColorMatrix and Path functionalities.

Several sub objects are included:
ABPaint: a wrapper for thePaint class
ABMatrix: a wrapper for the Matrix class
ABRegion: a wrapper for the Region class
ABColorMatrix: a wrapper for the ColorMatrix class
ABRgbFunctions: several functions to manipulate RGB values

Also two extended classes
ABRectF: a wrapper around the RectF class. B4A contains the Rect class, but to use some of the functions of this library I needed the float version of Rect.
ABPath: a full wrapper for the Path class. B4A contains the Path class but only exposes LineTo. ABPath exposes all functions (like addArc, addOval, etc…)

This library is to big to list all the functions, but a lot of them are used in the attached demo. It is a B4A translation of the Thermometer project on Mind The Robot http://mindtherobot.com/blog/272/android-custom-ui-making-a-vintage-thermometer/

How to use this library:

The main object is ABExtDrawing. You pass the B4A canvas to each function:

Sub Globals
        Dim ExDraw As ABExtDrawing
        Dim MyCanvas As Canvas
        Dim Panel1 as Panel
end Sub

Sub Activity_Create(FirstTime As Boolean)
        If FirstTime Then
		Activity.LoadLayout(&quot;2&quot;)
		MyCanvas.Initialize(Panel1)
	End If
        drawRim(MyCanvas)
End Sub

Sub drawRim(Canv As Canvas)
	' first, draw the metallic body
	ExDraw.drawOval(Canv, rimRect, rimPaint)
	' now the outer rim circle
	ExDraw.drawOval(Canv, rimRect, rimCirclePaint)
End Sub

The fun part is you can create all kind of Paints:

        ' the linear gradient Is a Bit skewed For realism
	rimPaint.Initialize
	rimPaint.SetFlags(rimPaint.flag_ANTI_ALIAS_FLAG)
	rimPaint.SetLinearGradient2(1,0.40, 0.0, 0.60, 1.0, Colors.RGB(0xf0, 0xf5, 0xf0),Colors.RGB(0x30, 0x31, 0x30),rimPaint.ShaderTileMode_CLAMP)
	rimPaint.DoShaderSingle(1)

	rimCirclePaint.Initialize
	rimCirclePaint.SetAntiAlias(True)
	rimCirclePaint.SetStyle(rimCirclePaint.Style_STROKE)
	rimCirclePaint.SetColor(Colors.ARGB(0x4f, 0x33, 0x36, 0x33))
	rimCirclePaint.SetStrokeWidth(0.005)

Or make extended Paths:

        handPath.Initialize
	handPath.moveTo(0.5, 0.5 + 0.2)
	handPath.lineTo(0.5 - 0.010, 0.5 + 0.2 - 0.007)
	handPath.lineTo(0.5 - 0.002, 0.5 - 0.32)
	handPath.lineTo(0.5 + 0.002, 0.5 - 0.32)
	handPath.lineTo(0.5 + 0.010, 0.5 + 0.2 - 0.007)
	handPath.lineTo(0.5, 0.5 + 0.2)
	handPath.addCircle(0.5, 0.5, 0.025, handPath.Direction_CW)

You can also use the Save and Restore functions of the canvas:

Sub drawScale(Canv As Canvas)
	ExDraw.drawOval(Canv, scaleRect, ScalePaint)

	ExDraw.save2(Canv, ExDraw.MATRIX_SAVE_FLAG)
	Dim i As Int
	Dim y1 As Float
	Dim y2 As Float
	Dim value As Int
	Dim valueString As String
	For i = 0 To totalNicks
		y1 = scaleRect.top
		y2 = y1 - 0.020

		ExDraw.drawLine(Canv, 0.5, y1, 0.5, y2, ScalePaint)

		If (i Mod 5 = 0) Then
			value = nickToDegree(i)
			If (value &gt;= minDegrees AND value &lt;= maxDegrees) Then
				valueString = value
				ExDraw.drawText(Canv, valueString, 0.5, y2 - 0.015, ScalePaint)
			End If
		End If

		ExDraw.rotate2(Canv, degreesPerNick, 0.5, 0.5)
	Next
	ExDraw.restore(Canv)
End Sub

And write filters like this GreyScale filter:

Sub GrayScale(bmp As Bitmap) As Bitmap
    Dim bmpGrayscale As Bitmap
    bmpGrayscale.InitializeMutable(bmp.Width, bmp.height)
    Dim c As Canvas
    c.Initialize2(bmpGrayscale)

    Dim paint As ABPaint
    paint.Initialize

    Dim mat As ABColorMatrix
    mat.Initialize
    mat.SetSaturation(0)

    paint.SetColorMatrixColorFilter2(mat)

    ExDraw.drawBitmap2(c, bmp, 0, 0, paint)

    Return bmpGrayscale
End Sub

Because of all the possibilities this library has, I may do some more articles on this blog.

For more information on what you can do with the library, look into the Android Documentation http://developer.android.com/reference/android/graphics/Canvas.html

As a registered user, you can download the library from the Basic4Android website
The demo project can be downloaded from http://www.gorgeousapps.com/ABExtDrawingDemo.zip

Click here to Donation if you like my work

12Scan: additional

Some people asked me what the output of 12Scan looks like. Well, it’s a plain TXT file with the matrix in it. A zero if it is not checked, A one if the user checked it. Any other program can then use this data how they want.

Here is the output of the demo: