Coordinates坐标

The Java 2D API maintains two coordinate spaces:Java 2D API维护两个坐标空间：

• User space用户空间 – The space in which graphics primitives are specified指定图形基本体的空间
• Device space设备空间 – The coordinate system of an output device such as a screen, window, or a printer输出设备（如屏幕、窗口或打印机）的坐标系

User space is a device-independent logical coordinate system, the coordinate space that your program uses.用户空间是独立于设备的逻辑坐标系，即程序使用的坐标空间。All geometries passed into Java 2D rendering routines are specified in user-space coordinates.传递到Java 2D渲染例程中的所有几何体都在用户空间坐标中指定。

When the default transformation from user space to device space is used, the origin of user space is the upper-left corner of the component's drawing area.使用从用户空间到设备空间的默认转换时，用户空间的原点位于零部件绘图区域的左上角。The x coordinate increases to the right, and the y coordinate increases downward, as shown in the following figure.x坐标向右增加，y坐标向下增加，如下图所示。The top-left corner of a window is 0,0.窗口的左上角为(0,0)。All coordinates are specified using integers, which is usually sufficient.所有坐标都是使用整数指定的，这通常就足够了。However, some cases require floating point or even double precision which are also supported.但是，在某些情况下，也支持浮点甚至双精度。

Device space is a device-dependent coordinate system that varies according to the target rendering device.设备空间是一个依赖于设备的坐标系，它随目标渲染设备的不同而变化。Although the coordinate system for a window or screen might be very different from the coordinate system of a printer, these differences are invisible to Java programs.尽管窗口或屏幕的坐标系可能与打印机的坐标系非常不同，但Java程序看不到这些差异。The necessary conversions between user space and device space are performed automatically during rendering.渲染过程中会自动执行用户空间和设备空间之间的必要转换。