April 2014 - Pharo-users - lists.pharo.org

Drag and drop items between list views
by MartinW April 7, 2014

April 7, 2014

Hi, i have to make a UI where users can sort items (sentences) into different collections by dragging and dropping them between list views. Is this possible with the widgets currently available in Pharo? M. -- View this message in context: http://forum.world.st/Drag-and-drop-items-between-list-views-tp4752285.html Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.

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[spec] set ballonText on a treeNode
by Emilio Oca April 7, 2014

April 7, 2014

Hi I think this is spec related. How can I set a ballonText on aTreeNode? I was expecting something like: tree childrenBlock: [ :anObject | self childrenFor: anObject ]; displayBlock: [ :anObject | self labelFor: anObject ]; helpBlock: [ :anObject | self helpFor: anObject ]; . but the last one is not available and I can not find something suitabe. How is the expected way? Best Emilio

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free learnig book
by Roelof Wobben April 7, 2014

April 7, 2014

Hello, I wonder if there is a free book with a lot of exercises so I can practice and learn a lot about Smalltalk. Roelof

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changes and sources file availability
by Usman Bhatti April 6, 2014

April 6, 2014

Hello, In Pharo 2.0, we could enforce the image not to look for sources and changes file at the startup with: SmalltalkImage checkChangesFileAvailability: false; checkSourcesFileAvailability: false. I could not found these selectors anymore in my Pharo 3.0 image. Clement mentioned to me a while ago that it was due to the change of compiler (Opal) and it might not be safe to remove these files (if I remember correctly). So, my question: 1/ Can I remove these two files safely from my production image? 2/ If the answer to 1/ is yes, how can I tell my image not to look for these files at image startup? tx, Usman

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JPEG support in Artifact
by Stephan Eggermont April 4, 2014

April 4, 2014

Reg Krock took a look at how difficult it would be to port Artefact to Gemstone. He found that JPEG support uses a plugin based reader/writer, and seems to render the JPEG using BitBlt and Form. Why are JPEGs rendered? Iâd think embedding them should be enough (and be better for speed and image quality) Stephan

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Few questions about Spec (instance specific layout and skinning)
by Thomas Bany April 4, 2014

April 4, 2014

Hi ! First, I apologyse for the wall of text. I'm trying my hands at Spec and I have few questions: - How can I implement an instance-dependent layout ? Regarding the layout method lookup, the documentation states that it "starts on instance side, which allows a UI to have a more specific layout depending on the state of the instance" I tried to simply put a layout in an instance method with the *<spec: #default>* pragma. But not only was it not retrieved by *ComposableModel>#defaultSpecSelector* but *ComposableModel>#retrieveSpec:*will send the selector on the class anyway. What I ended up doing was overiding #openWithSpec (which worked) but I'm pretty sure that my model is not composable at all. - Is it possible to change the "skin" of the basic widget ? I would like to implement some sort of toggle button by changing the color of ButtonModel and so far, I failed. I was not able to trace my color change up to the PluggableButtonMorph because it seems to use anoucement and I'm a Smalltalk rookie. I tried however to send #color: directly to the morph which does nothing: the #changed method rolls it back to its previous value. So I may be doing something wrong but it doesn't feel like the issue comes from Spec. Any clue ? - On a side note, I tried to send an argument to the selector that retrieve a widget in the layout method. And I came up with this : layout *add:* {#buttonAt: . 1}; *add:* {#buttonAt: . 2}; *add:* {#buttonAt: . 3} Is it how it's done ? Thanks in advance ! Thomas.

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Complex spec example
by Norbert Hartl April 3, 2014

April 3, 2014

Is there a rather complex example available that uses spec. I mean a sort of a complex UI that solves some real use cases from where I can steal ideas and patterns how things are done. Iâm just a UI noop and like to have all the guidance available :) thanks, Norbert

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Question on style
by nacho April 3, 2014

April 3, 2014

I'm writing a little app to calculate the roots of quadratic equations. The first step is to build the model and then I would like to link this model with a Spec GUI. So far the model is almost done (I have to solve yet imaginary roots). Would you consider this good code? Would you change something? or re-arrange the code? This is what I have so far: "The idea is to have a class to calculate quadratic equations. This first draft only calculates real roots (leaving aside imaginary roots). A QuadraticEquation is a class used to solve Quadratic Equations of the form: ax^2 + bx + c = 0, where a is not 0. You can set the coefficients one by one using: self quadraticCoefficient: aNumber self linearCoefficient: aNumber self constant: aNumber." Object subclass: #QuadraticEquation instanceVariableNames: 'quadraticCoefficient linearCoefficient constant checkTerm root1 root2' classVariableNames: '' category: 'IS-Math' "I create the accessors and then the following methods" QuadraticEquation>>calculateRoots checkTerm := ((linearCoefficient squared) - ( 4 * quadraticCoefficient * constant)) . self checkNegativeSqrt. QuadraticEquation>>checkNegativeSqrt self checkTerm >= 0 ifTrue: [ root1 := ((linearCoefficient negated) + (checkTerm sqrt)) / (2 * quadraticCoefficient). root2 := ((linearCoefficient negated) - (checkTerm sqrt)) / (2 * quadraticCoefficient) ] ifFalse: [ ^ 'Error: Negative square root']. "Example: -3x^2+2x+2=0 root1 = -0.5485837703548636 root2 = 1.2152504370215302 print(it) | anEquation | anEquation := QuadraticEquation new. anEquation quadraticCoefficient: -3. anEquation linearCoefficient: 2. anEquation constant: 2. anEquation calculateRoots. anEquation root1. Then change the last line to 'anEquation root2' to get the other root." Thanks so much for the input. Best regards Nacho ----- Nacho Smalltalker apprentice. Buenos Aires, Argentina. -- View this message in context: http://forum.world.st/Question-on-style-tp4752165.html Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.

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Rewiting code: doc?
by phil＠highoctane.be April 3, 2014

April 3, 2014

Hello, I'd like to get code rewritten automatically for a number of packages and classes. Basically I've got a bunch of packages and classes starting with a given prefix (like XXXThis and XXXThat) and I'd like to get them to be ZZZThis and ZZZThat. Of course, I want all the source code to follow suit. I saw the option in the Nautilus menu, but that's quite obscure. I googled around and read the Flamel thing in the book but that didn't helped me. Clues? Phil

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leansleft problem
by Roelof Wobben April 2, 2014

April 2, 2014

If I understood everything well on page 26 my Cell initialize must look like this: initialize super initialize. self initializeActiveSegments. self initializeExitSides. self leanleft. The Blankcell initialize must look like this : initialize super initialize. self initializeExitSides. And the MirrorCell initialize must look like this : initialize super initialize self leansLeft: true Why then I see a message that leanleft is not Understood in Blankcell. or do I misunderstood that page. I find it a very confusing page. Roelof

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