补充 添加图标 方法.

Signed-off-by: lion.chan <cy187lion@sina.com>

Software/Development/Environment/Qt/Qt_使用技巧.md

@@ -18,6 +18,42 @@ export QT_DEBUG_PLUGINS=1
 
 可在直行程序时打印 PLUGINS 信息，以确认某些插件是否被正确加载。
 
+## 添加图标
+
+### 制作图标
+
+先安装 ImageMagic 工具，并将其添加到系统 PATH 下方便使用。
+
+使用以下命令将多个不同尺寸的图片打包成一个 ICO 文件。
+
+```sh
+magick.exe convert icon-16.png icon-32.png icon-256.png myappico.ico
+```
+
+### 添加图标到应用
+
+在 Qt .pro 文件中添加以下内容，以便将图标编译到 Qt 程序中：
+
+```sh
+RC_ICONS = myappico.ico
+```
+
+However, if you already have an .rc file, for example, with the name myapp.rc, which you want to reuse, the following two steps will be required. First, put a single line of text to the myapp.rc file:
+
+```sh
+IDI_ICON1               ICON    "myappico.ico"
+```
+
+Then, add this line to your myapp.pro file:
+
+```sh
+RC_FILE = myapp.rc
+```
+
+If you do not use qmake, the necessary steps are: first, create an .rc file and run the rc or windres program on the .rc file, then link your application with the resulting .res file.
+
+更详细内容见《[Setting the Application Icon](https://doc.qt.io/qt-5/appicon.html)》。
+
 ## Windows 下程序打包
 
 可通过