2017 Google Summer of Code - Port Cricket to use Toga, instead of Tkinter

After almost 4 months of work on Google Summer of Code 2017, finally I'm completing my proposal. Every widget migration and every commit/PR/issue/discussion with my mentors about Cricket , Toga and Rubicon-ObjC were detailed on the Issue 58.

"Eating your own dog food"

The best way to show that a product is reliable to the customers is use it. So, the way to show that Toga is an effective tool to build a GUI is to build a complete application using it.

Cricket is a graphical tool that helps you run your test suites. Its current version is implemented using Tkinter as the main GUI framework. So, why not test Toga inside of another product from BeeWare? That's what I have accomplished during my GSoC work.

Results

The proposal focus not only on the port of Tkinter to Toga, but on mapping the necessary widgets for a real application using Toga framework. To help me to map this I studied more about Tkinter, Toga, Colosseum, Rubicon-ObjC, Objective-C, Cocoa and CSS.

The work I did during GSoC were sent through the PR 65, reported on the Issue 58 and the final demonstration of the work can be seen in this link. There were widgets used on Cricket that weren't ready yet on Toga, so some improvements were necessary on Toga so that I could use them on Cricket. In summary here are some PRs and issues that I contributed to get my work done in Cricket:

Open PR that I sent to Toga:

• PR 201 : [Core][Cocoa] Refactoring of the Tree widget

Merged PRs that I sent to Toga:

• PR 112 : [Core][Cocoa] Enable/disable state for buttons, solved Issue 91
• PR 170 : [Cocoa] Content and retry status for stack trace dialog
• PR 172 : [Cocoa] Window resize
• PR 173 : [Core][Cocoa] Button color
• PR 174 : [Doc] Examples folder and button features example
• PR 178 : [Doc] Fix tutorial 2 setup
• PR 180 : [Doc] Update Toga widgets roadmap
• PR 182 : [Cocoa] Update the label of the Stack trace button for critical dialog
• PR 184 : [Core][Cocoa] Hide/show boxes widget
• PR 188 : [Cocoa] Fix error on MultilineTextInput widget, solved Issue 187
• PR 204 : [Core][Cocoa] Clear method to MultilineTextInput widget, solved Issue 203
• PR 206 : [Core][Cocoa] Read-only and placeholder for MultilineTextInput widget
• PR 208 : [Cocoa] Fix apply style to a SplitContainer widget, solved Issue 207

Merged PR that I sent to Cricket:

• PR 60 : Fix test coverage, solved Issue 59

Merged PR that I sent to rubicon-objc:

• PR 34 : [Doc] Add reference to NSObject

Open issues that I sent to Toga:

• Issue 175 : [Core] Add more properties for Label and Font widgets
• Issue 176 : [Core] Add "rehint()" on the background of the widget after changing font size
• Issue 186 : [Core] Set initial position of the divisor of a SplitContainer
• Issue 197 : [Core] Get the id of the selected Tab View on the OptionContainer

Closed issues that I reported to Toga:

• Issue 167 : [Cocoa] Addition of a SplitContainer on a Box doesn't show the SplitContainer, was fixed by Russell Keith-Magee
• Issue 168 : [Cocoa] Addition of 2 boxes on an OptionContainer emits Rubicon's error, was fixed by Russell Keith-Magee
• Issue 169 : [Cocoa] Addition of 2 empty boxes on an OptionContainer emits error from Toga Cocoa platform, was fixed by Russell Keith-Magee
• Issue 181 : [Core][Cocoa] "Hide" option for widgets, was solved by me
• Issue 187 : [Cocoa] Errors on MultilineTextInput, was fixed by me
• Issue 189 : [Cocoa] ProgressBar doesn't appears in a Box, was fixed by Jonas Schell
• Issue 194 : [Cocoa] The frame of the MultilineTextInput doesn't appear, was fixed by Russell Keith-Magee
• Issue 195 : [Cocoa] ProgressBar doesn't appear inside of a Box oriented by row, was fixed by Russell Keith-Magee
• Issue 196 : [Cocoa] Set max value and value on a ProgressBar doesn't make any effect on the layout, was fixed by Russell Keith-Magee
• Issue 203 : [Core][Cocoa] Clear text on MultilineTextInput widget, was solved by me
• Issue 207 : [Cocoa] Set SplitContainer height doesn't update its size, was solved by me

Closed issues that I didn't reported but I solved on Toga:

• Issue 91 : API to disable buttons?
• Issue 205 : adding MultilineTextInput results in TypeError

Closed issue that I reported to Cricket:

• Issue 59 : Run selected doesn't count/ runs every test selected in a test module, was fixed by me

Open issue that I reported to rubicon-objc Jonas Obrist repository:

• Issue 1 : Segfault when iterate through a NSIndexSet using block notation

Future Plans

There are some features on Cricket that I want to help develop in a near future, for example:

• A button to refresh all the tests tree
• Cricket settings

Also, there are some issues remained after this migration to Toga. These issues will be fixed on Toga widgets in a near future too, for example:

• A gap between the output and error boxes when there is no output message
• Run a test if the user click on it

I truly believe that Toga will be the official framework on Python to build GUI for multi-platform applications, so I'll continue to contribute to this project because I want to use in every application that I would need a GUI.

Final Considerations

I would like to truly thank my mentors Russell Keith-Magee and Elias Dorneles for guide and help me so much during this period. The opportunity to be part of this community was a great honor to me, thank you so much to accept me in this program Russell Keith-Magee. Also, I want to thank Philip James that made some reviews in my PRs and Jonas Schell that fixed one issue that I sent to Toga.