OOP question
BlitzMax Forums/BlitzMax Beginners Area/OOP question
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| Hi there, a question on types and scope I guess. If I declare a type and in that type declare: Field imgFont:TImage Then in a method of the same type have the following: imgFont= LoadAnimImage("font16p.png",16,16,0,.. 126-32+1,DYNAMICIMAGE|MASKEDIMAGE) will the contents of imgFont be available to other methods in that type? Doesnt seem to be... Thanks for the help - a grateful newbie ;-) |
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| will the contents of imgFont be available to other methods in that type? Yes, but not to functions. Got code? |
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| Here it is..... Strict Graphics 640,480,0 HideMouse Type TFont Field iLastASCII=126 Field iFirstASCII=32 Field iCellWidth=16 Field iCellHeight=16 Field imgFont: TImage Field iWidthTable[iLastASCII-iFirstASCII+1] Method CreateFont(sFontName$) Local iMaxWidth=0 Local i,x,y,alpha=0 'Local imgfont SetMaskColor (255,0,255) imgFont= LoadAnimImage("font16p.png",16,16,0,.. 126-32+1,DYNAMICIMAGE|MASKEDIMAGE) If Not imgfont Print "cant fin font" For i=1 To (iLastASCII-iFirstASCII) Local img=LockImage(imgFont,i) For x=(iCellWidth-1) To 0 Step -1 For y=0 Until iCellHeight alpha=ReadPixel(img,x,y) & $ff000000 If alpha Then Exit Next If alpha Then Exit Next UnlockImage imgFont,i iWidthTable[i]=x+1 If x>iMaxWidth Then iMaxWidth=x Next iWidthTable[0]=iMaxWidth*.3 EndMethod Method DrawBmpFont(text$,x,y) Local i=0 For i=0 Until text.length DrawImage imgFont,x,y,Asc(text[i..i+1])-32 x:+iWidthTable[Asc(text[i..i+1])-32] Next EndMethod EndType Local ArialFont:TFont ArialFont = New TFont ArialFont.iFirstASCII = 32 ArialFont.iLastASCII = 126 ArialFont.iCellWidth = 16 ArialFont.iCellHeight = 16 ArialFont.CreateFont("font16p.png") While Not KeyDown(key_escape) ArialFont.DrawBmpFont("Hello",100,100) Flip Cls Wend ...basically I want to know if the DrawBmpFont method can access imgFont. Thanks |
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| This works here (BlitzMAX 1.14), and isn't significantly different from your example: The DrawBmpFont method can access imgFont just fine. Maybe your PNG file is corrupted or something? |
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| I've got it working at the expense of getting very confused. The following code works: ***************************************** Strict Graphics 640,480,0 HideMouse Type TFont Field iLastASCII=126 'Local as it may need to be different for each font object Field iFirstASCII=32 'Local as it may need to be different for each font object Field iCellWidth Field iCellHeight Field imgFont: TImage ' Local as it needs to specific to each instance (each font) Field iWidthTable[iLastASCII-iFirstASCII+1] ' Again, local Method CreateFont(sFontName$) 'try it without the $ if there's a problem - check later Local iMaxWidth=0 Local i,x,y,alpha=0 SetMaskColor (255,0,255) imgFont= LoadAnimImage("font16p.png",16,16,0,.. 126-32+1,DYNAMICIMAGE|MASKEDIMAGE) If Not imgfont Print "Cant find font to load" For i=1 To (iLastASCII-iFirstASCII) ' step through each character Local img=LockImage(imgFont,i) ' lock character image so we can read pixels - AL Lock image allows us to access image's pixels. Look at each frame of image For x=(iCellWidth-1) To 0 Step -1 ' work from right to left For y=0 Until iCellHeight ' check pixels from top to bottom alpha=ReadPixel(img,x,y) & $ff000000 ' grab alpha ($00=background, $ff=foreground) If alpha Then Exit ' if foreground then we have our width (in x) Next If alpha Then Exit ' if we have our width, no need to continue Next UnlockImage imgFont,i ' unlock this character iWidthTable[i]=x+1 ' store width plus spacing If x>iMaxWidth Then iMaxWidth=x ' check against widest character Next iWidthTable[0]=iMaxWidth*.3 ' calculate width of space EndMethod Method DrawBmpFont(text$,x,y) Local i=0 For i=0 Until text.length DrawImage imgFont,x,y,Asc(text[i..i+1])-32 x:+iWidthTable[Asc(text[i..i+1])-32] Next EndMethod EndType Global ArialFont:TFont ArialFont = New TFont ArialFont.iFirstASCII = 32 ArialFont.iLastASCII = 126 ArialFont.iCellWidth = 16 ArialFont.iCellHeight = 16 ArialFont.CreateFont("font16p.png") While Not KeyDown(key_escape) ArialFont.DrawBmpFont("1. Hello this is a font test",100,100) ArialFont.DrawBmpFont("2. More text for you",100,200) Flip Cls Wend ***************************************** BUT...if you change the first 2 lines of the type to: Field iLastASCII 'Local as it may need to be different for each font object Field iFirstASCII ie you remove the values within the type, the following line: iWidthTable[i]=x+1 ..produces the error 'Unhandled Exception: Attempt to index array element beyond array length' So what is the difference? I understand the error but have no idea why this would happen. What have I missed? Thanks very much for all help. |
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| use {codebox} ... {/codebox} replace {} with [] |
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| - sorry, dont understand your last comment replace {} with [] ? In terms of the code the problem I have found is that iWidthTable doesnt seem to have a size - yet its size seems to be initialised to iWidthTable[iLastASCII-iFirstASCII+1], with iLastASCII and iFirstASCII set when I create the instance... |
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| When you want to post long code type "[" followed by "codebox" and a closing "]" on a line. Then type your code, and when you are done type "[" followed by "/" and "codebox" and a final "]". Check out the forum codes here |
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| I got ya. Thanks |
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