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Drawing text with opaque background?

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Carl Gundel-2

Drawing text with opaque background?

What's the best way to draw text on a graphics context with an opaque
background?

Thanks,

-Carl Gundel
http://www.libertybasic.com
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Maarten Mostert

Re: Drawing text with opaque background?

http://www.cairographics.org/

Cheers,

Maarten,

-----Original Message-----
From: "Carl Gundel" <[hidden email]>
Sent: Saturday, 17 November, 2012 20:54
To: [hidden email]
Subject: [vwnc] Drawing text with opaque background?

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Boris Popov, DeepCove Labs (SNN)

Re: Drawing text with opaque background?

In reply to this post by Carl Gundel-2

gc := Window currentWindow graphicsContext.

gc newCairoContextWhile:

[:cr |

| layout |

layout := (cr newLayout)

text: 'Hello, World!';

fontDescriptionString: 'arial bold 10';

yourself.

source: ColorValue red;

rectangle: (50 @ 150 extent: layout extent);

fill;

source: ColorValue black;

moveTo: 50 @ 150.

layout showOn: cr].

-Boris

From: [hidden email] [mailto:[hidden email]] On Behalf Of [hidden email]
Sent: Monday, November 19, 2012 9:12 AM
To: [hidden email]
Cc: [hidden email]
Subject: Re: [vwnc] Drawing text with opaque background?

http://www.cairographics.org/

Cheers,

Maarten,

-----Original Message-----
From: "Carl Gundel" <[hidden email]>
Sent: Saturday, 17 November, 2012 20:54
To: [hidden email]
Subject: [vwnc] Drawing text with opaque background?

_______________________________________________
vwnc mailing list
[hidden email]
http://lists.cs.uiuc.edu/mailman/listinfo/vwnc

Carl Gundel

Re: Drawing text with opaque background?

Thanks guys but I'm not using Cairo.

-Carl Gundel

Liberty BASIC for Windows - http://www.libertybasic.com

Run BASIC, easy web programming - http://www.runbasic.com

On Nov 19, 2012, at 9:32 AM, "Boris Popov, DeepCove Labs" <[hidden email]> wrote:

gc := Window currentWindow graphicsContext.

gc newCairoContextWhile:

                                [:cr |

                                | layout |

                                layout := (cr newLayout)

                                                                                text: 'Hello, World!';

                                                                                fontDescriptionString: 'arial bold 10';

                                                                                yourself.

                                cr

                                                source: ColorValue red;

                                                rectangle: (50 @ 150 extent: layout extent);

                                                fill;

                                                source: ColorValue black;

                                                moveTo: 50 @ 150.

                                layout showOn: cr].

<image001.png>

-Boris

From: [hidden email] [[hidden email]] On Behalf Of [hidden email]
Sent: Monday, November 19, 2012 9:12 AM
To: [hidden email]
Cc: [hidden email]
Subject: Re: [vwnc] Drawing text with opaque background?

http://www.cairographics.org/

Cheers,

Maarten,

-----Original Message-----
From: "Carl Gundel" <[hidden email]>
Sent: Saturday, 17 November, 2012 20:54
To: [hidden email]
Subject: [vwnc] Drawing text with opaque background?

What's the best way to draw text on a graphics context with an opaque
background?

Thanks,

-Carl Gundel
http://www.libertybasic.com
_______________________________________________
vwnc mailing list
[hidden email]
http://lists.cs.uiuc.edu/mailman/listinfo/vwnc

_______________________________________________
vwnc mailing list
[hidden email]
http://lists.cs.uiuc.edu/mailman/listinfo/vwnc

Steven Kelly

Re: Drawing text with opaque background?

Another way to do it: BackColor, from ExtraEmphases. You may of course reply that you’re not using ExtraEmphases J.

Steve

Carl Gundel wrote:

Thanks guys but I'm not using Cairo.

-Carl Gundel

Liberty BASIC for Windows - http://www.libertybasic.com

Run BASIC, easy web programming - http://www.runbasic.com

On Nov 19, 2012, at 9:32 AM, "Boris Popov, DeepCove Labs" <[hidden email]> wrote:

gc := Window currentWindow graphicsContext.
gc newCairoContextWhile:
                                [:cr |
                                | layout |
                                layout := (cr newLayout)
                                                                                text: 'Hello, World!';
                                                                                fontDescriptionString: 'arial bold 10';
                                                                                yourself.
                                cr
                                                source: ColorValue red;
                                                rectangle: (50 @ 150 extent: layout extent);
                                                fill;
                                                source: ColorValue black;
                                                moveTo: 50 @ 150.
                                layout showOn: cr].

<image001.png>

-Boris

From: [hidden email] [[hidden email]] On Behalf Of [hidden email]
Sent: Monday, November 19, 2012 9:12 AM
To: [hidden email]
Cc: [hidden email]
Subject: Re: [vwnc] Drawing text with opaque background?

http://www.cairographics.org/

Cheers,

Maarten,

-----Original Message-----
From: "Carl Gundel" <[hidden email]>
Sent: Saturday, 17 November, 2012 20:54
To: [hidden email]
Subject: [vwnc] Drawing text with opaque background?
What's the best way to draw text on a graphics context with an opaque
background?

Thanks,

-Carl Gundel
http://www.libertybasic.com
_______________________________________________
vwnc mailing list
[hidden email]
http://lists.cs.uiuc.edu/mailman/listinfo/vwnc

_______________________________________________
vwnc mailing list
[hidden email]
http://lists.cs.uiuc.edu/mailman/listinfo/vwnc

Boris Popov, DeepCove Labs (SNN)

Re: Drawing text with opaque background?

In reply to this post by Boris Popov, DeepCove Labs (SNN)

I would have a peek at WidgetState>>isOpaque: then and see the various senders, i.e. SimpleComponent>>displayBackgroundIfNeededOn:in:. I think it’ll ultimately come down to displaying a rectangle somewhere before painting the text either way you slice it.

-Boris

From: [hidden email] [mailto:[hidden email]] On Behalf Of Carl Gundel
Sent: Monday, November 19, 2012 10:05 AM
To: [hidden email]
Subject: Re: [vwnc] Drawing text with opaque background?

Thanks guys but I'm not using Cairo.

-Carl Gundel

Liberty BASIC for Windows - http://www.libertybasic.com

Run BASIC, easy web programming - http://www.runbasic.com

On Nov 19, 2012, at 9:32 AM, "Boris Popov, DeepCove Labs" <[hidden email]> wrote:

gc := Window currentWindow graphicsContext.

gc newCairoContextWhile:

                                [:cr |

                                | layout |

                                layout := (cr newLayout)

                                                                                text: 'Hello, World!';

                                                                                fontDescriptionString: 'arial bold 10';

                                                                                yourself.

                                cr

                                                source: ColorValue red;

                                                rectangle: (50 @ 150 extent: layout extent);

                                                fill;

                                                source: ColorValue black;

                                                moveTo: 50 @ 150.

                                layout showOn: cr].

<image001.png>

-Boris

From: [hidden email] [[hidden email]] On Behalf Of [hidden email]
Sent: Monday, November 19, 2012 9:12 AM
To: [hidden email]
Cc: [hidden email]
Subject: Re: [vwnc] Drawing text with opaque background?

http://www.cairographics.org/

Cheers,

Maarten,

-----Original Message-----
From: "Carl Gundel" <[hidden email]>
Sent: Saturday, 17 November, 2012 20:54
To: [hidden email]
Subject: [vwnc] Drawing text with opaque background?

What's the best way to draw text on a graphics context with an opaque
background?

Thanks,

-Carl Gundel
http://www.libertybasic.com
_______________________________________________
vwnc mailing list
[hidden email]
http://lists.cs.uiuc.edu/mailman/listinfo/vwnc

_______________________________________________
vwnc mailing list
[hidden email]
http://lists.cs.uiuc.edu/mailman/listinfo/vwnc

Dave Stevenson-3

Re: Drawing text with opaque background?

In reply to this post by Carl Gundel

Here's some low level code. It does not first draw a background, so you'll have to do that if you want it. See senders of #displayFromCharacter:to:startX:forTranslation:on: to see higher level code.

...
aGraphicsContext paint: self selectionForegroundColor.

aComposedText
  displayFromCharacter: first
  to: last
  startX: startPoint left + self origin x
  forTranslation: self origin
  on: aGraphicsContext

Dave Stevenson
[hidden email]

From: Carl Gundel <[hidden email]>
To: "[hidden email]" <[hidden email]>
Sent: Mon, November 19, 2012 7:05:57 AM
Subject: Re: [vwnc] Drawing text with opaque background?

Thanks guys but I'm not using Cairo.

-Carl Gundel

Liberty BASIC for Windows - http://www.libertybasic.com

Run BASIC, easy web programming - http://www.runbasic.com

On Nov 19, 2012, at 9:32 AM, "Boris Popov, DeepCove Labs" <[hidden email]> wrote:

gc := Window currentWindow graphicsContext.

gc newCairoContextWhile:

                                [:cr |

                                | layout |

                                layout := (cr newLayout)

                                                                                text: 'Hello, World!';

                                                                                fontDescriptionString: 'arial bold 10';

                                                                                yourself.

                                cr

                                                source: ColorValue red;

                                                rectangle: (50 @ 150 extent: layout extent);

                                                fill;

                                                source: ColorValue black;

                                                moveTo: 50 @ 150.

                                layout showOn: cr].

<image001.png>

-Boris

From: [hidden email] [[hidden email]] On Behalf Of [hidden email]
Sent: Monday, November 19, 2012 9:12 AM
To: [hidden email]
Cc: [hidden email]
Subject: Re: [vwnc] Drawing text with opaque background?

http://www.cairographics.org/

Cheers,

Maarten,

-----Original Message-----
From: "Carl Gundel" <[hidden email]>
Sent: Saturday, 17 November, 2012 20:54
To: [hidden email]
Subject: [vwnc] Drawing text with opaque background?

What's the best way to draw text on a graphics context with an opaque
background?

Thanks,

-Carl Gundel
http://www.libertybasic.com
_______________________________________________
vwnc mailing list
[hidden email]
http://lists.cs.uiuc.edu/mailman/listinfo/vwnc

_______________________________________________
vwnc mailing list
[hidden email]
http://lists.cs.uiuc.edu/mailman/listinfo/vwnc

Dave & Vicki Stevenson

Re: Drawing text with opaque background?

In reply to this post by Carl Gundel

Here's some low level code. It does not first draw a background, so you'll have to do that if you want it. See senders of #displayFromCharacter:to:startX:forTranslation:on: to see higher level code.

...
aGraphicsContext paint: self selectionForegroundColor.

aComposedText
  displayFromCharacter: first
  to: last
  startX: startPoint left + self origin x
  forTranslation: self origin
  on: aGraphicsContext

Dave Stevenson
[hidden email]

From: Carl Gundel <[hidden email]>
To: "[hidden email]" <[hidden email]>
Sent: Mon, November 19, 2012 7:05:57 AM
Subject: Re: [vwnc] Drawing text with opaque background?

Thanks guys but I'm not using Cairo.

-Carl Gundel

Liberty BASIC for Windows - http://www.libertybasic.com

Run BASIC, easy web programming - http://www.runbasic.com

On Nov 19, 2012, at 9:32 AM, "Boris Popov, DeepCove Labs" <[hidden email]> wrote:

gc := Window currentWindow graphicsContext.

gc newCairoContextWhile:

                                [:cr |

                                | layout |

                                layout := (cr newLayout)

                                                                                text: 'Hello, World!';

                                                                                fontDescriptionString: 'arial bold 10';

                                                                                yourself.

                                cr

                                                source: ColorValue red;

                                                rectangle: (50 @ 150 extent: layout extent);

                                                fill;

                                                source: ColorValue black;

                                                moveTo: 50 @ 150.

                                layout showOn: cr].

<image001.png>

-Boris

From: [hidden email] [[hidden email]] On Behalf Of [hidden email]
Sent: Monday, November 19, 2012 9:12 AM
To: [hidden email]
Cc: [hidden email]
Subject: Re: [vwnc] Drawing text with opaque background?

http://www.cairographics.org/

Cheers,

Maarten,

-----Original Message-----
From: "Carl Gundel" <[hidden email]>
Sent: Saturday, 17 November, 2012 20:54
To: [hidden email]
Subject: [vwnc] Drawing text with opaque background?

What's the best way to draw text on a graphics context with an opaque
background?

Thanks,

-Carl Gundel
http://www.libertybasic.com
_______________________________________________
vwnc mailing list
[hidden email]
http://lists.cs.uiuc.edu/mailman/listinfo/vwnc

_______________________________________________
vwnc mailing list
[hidden email]
http://lists.cs.uiuc.edu/mailman/listinfo/vwnc

Samuel S. Shuster-2

Re: Drawing text with opaque background?

In reply to this post by Carl Gundel-2

Carl,

> What's the best way to draw text on a graphics context with an opaque
> background?

First, there are the concepts, some of which you probably know, but for completeness I'll include.

You draw with a GraphicsContext. A GraphicsContext knows nothing about foreground or background. It is just a, possibly clipped and/or offset area associated with the the screen or a window that you paint on.

It knows nothing about erasing or things that are "under" it.

Your job in effect is to fake the person who is looking at what you are drawing into perceiving that there is background and foreground and so on.

So, lets say you have a Rectangle (50 @ 50 extent: 100 @ 100) you want to draw opaque text on, which perhaps has other things already drawn on.

You first "Fill" the area with background color using the current background color:

aGraphicsContext paint: aWidgetOrWindow backgroundColor.
aGraphicsContext displayRectangle: 50 @ 50

Then you set the foreground/font color and display a string

aGraphicsContext paint: aWidgetOrWindow foregroundColor.
aGraphicsContext displayString: 'HiHo' at: 50 @ 74

Now, why at 74 and not 50? That is because text is displayed with the Y "0" at the baseline, which you can think of as the point that the two diagonal lines of the letter v meet.

If you wanted to be more exact, you could ask the current TextAttributes/widget textStyle for #baseline, and add that to the top of your rectangle.

FWIW, if you are actually using a Text, you can instead use:

aText displayOn: aGraphicsContext at: 50 @ 74

Yes, the 7 years leading the GUI project still has some echoes in my head.

And So It Goes
Sames
______________________________________________________________________

Samuel S. Shuster [|]

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Boris Popov, DeepCove Labs (SNN)

Re: Drawing text with opaque background?

In reply to this post by Dave Stevenson-3

Another approach is to load HotDraw then do,

gc := Window currentWindow graphicsContext.

text := (TextFigure string: 'Hello, World')

fillColor: ColorValue yellow;

opaque;

yourself.

text displayOn: gc at: 140@150.

-Boris

From: [hidden email] [mailto:[hidden email]] On Behalf Of Dave Stevenson
Sent: Monday, November 19, 2012 11:31 AM
To: Carl Gundel; [hidden email]
Subject: Re: [vwnc] Drawing text with opaque background?

Here's some low level code. It does not first draw a background, so you'll have to do that if you want it. See senders of #displayFromCharacter:to:startX:forTranslation:on: to see higher level code.

...
aGraphicsContext paint: self selectionForegroundColor.

aComposedText
  displayFromCharacter: first
  to: last
  startX: startPoint left + self origin x
  forTranslation: self origin
  on: aGraphicsContext

Dave Stevenson
[hidden email]

From: Carl Gundel <[hidden email]>
To: "[hidden email]" <[hidden email]>
Sent: Mon, November 19, 2012 7:05:57 AM
Subject: Re: [vwnc] Drawing text with opaque background?

Thanks guys but I'm not using Cairo.

-Carl Gundel

Liberty BASIC for Windows - http://www.libertybasic.com

Run BASIC, easy web programming - http://www.runbasic.com

On Nov 19, 2012, at 9:32 AM, "Boris Popov, DeepCove Labs" <[hidden email]> wrote:

gc := Window currentWindow graphicsContext.

gc newCairoContextWhile:

                                [:cr |

                                | layout |

                                layout := (cr newLayout)

                                                                                text: 'Hello, World!';

                                                                                fontDescriptionString: 'arial bold 10';

                                                                                yourself.

                                cr

                                                source: ColorValue red;

                                                rectangle: (50 @ 150 extent: layout extent);

                                                fill;

                                                source: ColorValue black;

                                                moveTo: 50 @ 150.

                                layout showOn: cr].

<image001.png>

-Boris

From: [hidden email] [[hidden email]] On Behalf Of [hidden email]
Sent: Monday, November 19, 2012 9:12 AM
To: [hidden email]
Cc: [hidden email]
Subject: Re: [vwnc] Drawing text with opaque background?

http://www.cairographics.org/

Cheers,

Maarten,

-----Original Message-----
From: "Carl Gundel" <[hidden email]>
Sent: Saturday, 17 November, 2012 20:54
To: [hidden email]
Subject: [vwnc] Drawing text with opaque background?

What's the best way to draw text on a graphics context with an opaque
background?

Thanks,

-Carl Gundel
http://www.libertybasic.com
_______________________________________________
vwnc mailing list
[hidden email]
http://lists.cs.uiuc.edu/mailman/listinfo/vwnc

_______________________________________________
vwnc mailing list
[hidden email]
http://lists.cs.uiuc.edu/mailman/listinfo/vwnc