| Development/Tutorials/Qt4 Ruby Tutorial/Chapter 09 | Current message text |
|---|---|
| ↓...Chapter 09/Page display title/ru | Разработка/Руководства/Введение в Qt4 на Ruby/Глава 9 |
| ↓...t4 Ruby Tutorial/Chapter 09/1/ru | TutorialBrowser/ru |
| ↓...t4 Ruby Tutorial/Chapter 09/2/ru | Введение в программирование на Qt<sup>®</sup>4 на языке Ruby |
| ↓...t4 Ruby Tutorial/Chapter 09/3/ru | Пушка детям не игрушка |
| ↓...t4 Ruby Tutorial/Chapter 09/4/ru | Пример 8: Готовься к битве |
| ↓...t4 Ruby Tutorial/Chapter 09/5/ru | Пример 10: Гладкий как шёлк |
| ↓...t4 Ruby Tutorial/Chapter 09/6/ru | == Пушка детям не игрушка == |
| ↓...t4 Ruby Tutorial/Chapter 09/7/ru | [[Image:Qt4_Ruby_Tutorial_Screenshot_9.png|center]] |
| ↓...t4 Ruby Tutorial/Chapter 09/8/ru | Файлы: |
| ↓...t4 Ruby Tutorial/Chapter 09/9/ru | === Обзор === |
| ↓...4 Ruby Tutorial/Chapter 09/10/ru | In this example we become graphic by drawing a cute little blue cannon. Only cannon.rb differs from the previous chapter. |
| ↓...4 Ruby Tutorial/Chapter 09/11/ru | === Построчный обзор программы === |
| ↓...4 Ruby Tutorial/Chapter 09/12/ru | We'll now start to use [http://doc.qt.nokia.com/latest/qpainter.html Qt::Painter] in earnest. We create a painter that operates on this widget. |
| ↓...4 Ruby Tutorial/Chapter 09/13/ru | The edges of what [http://doc.qt.nokia.com/latest/qpainter.html Qt::Painter] draws are drawn using the pen. Here we set it to [http://doc.qt.nokia.com/latest/qt.html#PenStyle-enum Qt::NoPen], meaning that there will be no special edge when we draw something. |
| ↓...4 Ruby Tutorial/Chapter 09/14/ru | When [http://doc.qt.nokia.com/latest/qpainter.html Qt::Painter] fills a rectangle, a circle, or whatever, it fills the shape using its brush. Here we set it to use a solid blue brush. (We could also use a pattern.) The blue brush will go all the way to the edges of the things we draw. |
| ↓...4 Ruby Tutorial/Chapter 09/15/ru | The [http://doc.qt.nokia.com/latest/qpainter.html#translate Qt::Painter::translate()] function translates the coordinate system of the [http://doc.qt.nokia.com/latest/qpainter.html Qt::Painter] (i.e., it moves it by an offset). Here we set the (0, 0) point to the bottom-left corner of the widget. The x and y directions remain unchanged, i.e., all the y coordinates inside the widget are now negative. (See [http://doc.qt.nokia.com/latest/coordsys.html The Coordinate System] for more information about Qt's coordinate system.) |
| ↓...4 Ruby Tutorial/Chapter 09/16/ru | The [http://doc.qt.nokia.com/latest/qpainter.html#drawPie Qt::Painter::drawPie()] function draws a pie shape inside the specified rectangle using a start angle and an arc length. The angles are specified in sixteenths of a degree. Zero degrees is at the 3 o'clock position. The drawing direction is counter-clockwise. Here we draw a quarter of a circle in the bottom-left corner of the widget. The pie is filled with blue and has no outline. |
| ↓...4 Ruby Tutorial/Chapter 09/17/ru | The [http://doc.qt.nokia.com/latest/qpainter.html#rotate Qt::Painter::rotate()] function rotates the coordinate system of the [http://doc.qt.nokia.com/latest/qpainter.html Qt::Painter] around the origin. The rotation argument is given in degrees (not given in sixteenths of a degree as above) and clockwise. Here we rotate the coordinate system '''<tt>@currentAngle</tt>''' degrees counter-clockwise. |
| ↓...4 Ruby Tutorial/Chapter 09/18/ru | The [http://doc.qt.nokia.com/latest/qpainter.html#drawRect Qt::Painter::drawRect()] function draws the specified rectangle. Here we draw the barrel of the cannon. |
| ↓...4 Ruby Tutorial/Chapter 09/19/ru | It can often be difficult to envision the resulting drawing when the coordinate system has been transformed (translated, rotated, scaled, or sheared) as above. |
| ↓...4 Ruby Tutorial/Chapter 09/20/ru | In this case the coordinate system is first translated and then rotated. If the rectangle [http://doc.qt.nokia.com/latest/qrect.html Qt::Rect].new(30, -5, 20, 10) had been drawn in the translated coordinate system, it would have looked like this: |
| ↓...4 Ruby Tutorial/Chapter 09/21/ru | [[Image:Qt4_Ruby_Tutorial_Screenshot_9-incorrect.png|center]] |
| ↓...4 Ruby Tutorial/Chapter 09/22/ru | Note that the rectangle is clipped by the border of the '''<tt>CannonField</tt>''' widget. When we rotate the coordinate system, for instance 60 degrees, the rectangle will be rotated around (0, 0), which is the bottom-left corner because we have translated the coordinate system. The result looks like this: |
| ↓...4 Ruby Tutorial/Chapter 09/23/ru | [[Image:Qt4_Ruby_Tutorial_Screenshot_9-correct.png|center]] |
| ↓...4 Ruby Tutorial/Chapter 09/24/ru | === Запуск приложения === |
| ↓...4 Ruby Tutorial/Chapter 09/25/ru | When the slider is operated the angle of the drawn cannon changes accordingly. |
| ↓...4 Ruby Tutorial/Chapter 09/26/ru | === Exercises === Set a different pen instead of [http://doc.qt.nokia.com/latest/qt.html#PenStyle-enum Qt::NoPen]. Set a patterned brush. |
| ↓...4 Ruby Tutorial/Chapter 09/27/ru | [[Category:Ruby/ru]] |
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