The Native Drawing module provides APIs for drawing 2D graphics and text. The following scenarios are common for drawing development:
* Drawing 2D graphics
* Drawing and painting text
## Available APIs
| API| Description|
| -------- | -------- |
| OH_Drawing_BitmapCreate (void) | Creates a bitmap object.|
| OH_Drawing_BitmapBuild (OH_Drawing_Bitmap *, const uint32_t width, const uint32_t height, const OH_Drawing_BitmapFormat *) | Initializes the width and height of a bitmap object and sets the pixel format for the bitmap.|
| OH_Drawing_CanvasCreate (void) | Creates a canvas object.|
| OH_Drawing_CanvasBind (OH_Drawing_Canvas *, OH_Drawing_Bitmap *) | Binds a bitmap to a canvas so that the content drawn on the canvas is output to the bitmap (this process is called CPU rendering).|
| OH_Drawing_CanvasAttachBrush (OH_Drawing_Canvas *, const OH_Drawing_Brush *) | Attaches a brush to a canvas so that the canvas will use the style and color of the brush to fill in a shape.|
| OH_Drawing_CanvasAttachPen (OH_Drawing_Canvas *, const OH_Drawing_Pen *) | Attaches a pen to a canvas so that the canvas will use the style and color of the pen to outline a shape.|
| OH_Drawing_CanvasDrawPath (OH_Drawing_Canvas *, const OH_Drawing_Path *) | Draws a path.|
| OH_Drawing_PathCreate (void) | Creates a path object.|
| OH_Drawing_PathMoveTo (OH_Drawing_Path *, float x, float y) | Sets the start point of a path.|
| OH_Drawing_PathLineTo (OH_Drawing_Path *, float x, float y) | Draws a line segment from the last point of a path to the target point. |
| OH_Drawing_PathClose (OH_Drawing_Path *) | Closes a path. A line segment from the start point to the last point of the path is added.|
| OH_Drawing_PenCreate (void) | Creates a pen object.|
| OH_Drawing_PenSetAntiAlias (OH_Drawing_Pen *, bool) | Checks whether anti-aliasing is enabled for a pen. If anti-aliasing is enabled, edges will be drawn with partial transparency.|
| OH_Drawing_PenSetWidth (OH_Drawing_Pen *, float width) | Sets the thickness for a pen. This thickness determines the width of the outline of a shape.|
| OH_Drawing_BrushCreate (void) | Creates a brush object.|
| OH_Drawing_BrushSetColor (OH_Drawing_Brush *, uint32_t color) | Sets the color for a brush. The color will be used by the brush to fill in a shape.|
| OH_Drawing_CreateTypographyStyle (void) | Creates a `TypographyStyle` object.|
| OH_Drawing_CreateTextStyle (void) | Creates a `TextStyle` object.|
| OH_Drawing_TypographyHandlerAddText (OH_Drawing_TypographyCreate *, const char *) | Sets the text content.|
| OH_Drawing_TypographyPaint (OH_Drawing_Typography *, OH_Drawing_Canvas *, double, double) | Paints text on the canvas.|
## Development Procedure for 2D Graphics Drawing
The following steps describe how to use the canvas and brush of the Native Drawing module to draw a 2D graphics.
1.**Create a bitmap object.** Use `OH_Drawing_BitmapCreate` in `drawing_bitmap.h` to create a bitmap object (named `cBitmap` in this example), and use `OH_Drawing_BitmapBuild` to specify its length, width, and pixel format.
2.**Create a canvas object.** Use `OH_Drawing_CanvasCreate` in `drawing_canvas.h` to create a canvas object (named `cCanvas` in this example), and use `OH_Drawing_CanvasBind` to bind `cBitmap` to this canvas. The content drawn on the canvas will be output to the bound `cBitmap` object.
3.**Construct a shape.** Use the APIs provided in `drawing_path.h` to draw a pentagram `cPath`.
```c++
int len = 300;
float aX = 500;
float aY = 500;
float dX = aX - len * std::sin(18.0f);
float dY = aY + len * std::cos(18.0f);
float cX = aX + len * std::sin(18.0f);
float cY = dY;
float bX = aX + (len / 2.0);
float bY = aY + std::sqrt((cX - dX) * (cX - dX) + (len / 2.0) * (len / 2.0));
float eX = aX - (len / 2.0);
float eY = bY;
// Create a path object and use the APIs to draw a pentagram.
OH_Drawing_Path* cPath = OH_Drawing_PathCreate();
// Specify the start point of the path.
OH_Drawing_PathMoveTo(cPath, aX, aY);
// Draw a line segment from the last point of a path to the target point.
OH_Drawing_PathLineTo(cPath, bX, bY);
OH_Drawing_PathLineTo(cPath, cX, cY);
OH_Drawing_PathLineTo(cPath, dX, dY);
OH_Drawing_PathLineTo(cPath, eX, eY);
// Close the path. Now the path is drawn.
OH_Drawing_PathClose(cPath);
```
4.**Set the brush and pen styles.** Use `OH_Drawing_PenCreate` in `drawing_pen.h` to create a pen (named `cPen` in this example), and set the attributes such as the anti-aliasing, color, and thickness. The pen is used to outline a shape. Use `OH_Drawing_BrushCreate` in `drawing_brush.h` to create a brush (named `cBrush` in this example), and set the brush color. The brush is used to fill in a shape. Use `OH_Drawing_CanvasAttachPen` and `OH_Drawing_CanvasAttachBrush` in `drawing_canvas.h` to attach the pen and brush to the canvas.
```c++
// Create a pen object and set the anti-aliasing, color, and thickness.
5.**Draw a shape.** Use `OH_Drawing_CanvasDrawPath` in `drawing_canvas.h` to draw a pentagram on the canvas. Call the corresponding APIs to destroy the objects when they are no longer needed.
```c++
// Draw a pentagram on the canvas. The outline of the pentagram is drawn by the pen, and the color is filled in by the brush.
OH_Drawing_CanvasDrawPath(cCanvas, cPath);
// Destroy the created objects when they are no longer needed.
OH_Drawing_BrushDestory(cBrush);
OH_Drawing_PenDestory(cPen);
OH_Drawing_PathDestory(cPath);
```
6.**Obtain pixel data.** Use `OH_Drawing_BitmapGetPixels` in `drawing_bitmap.h` to obtain the pixel address of the bitmap bound to the canvas. The memory to which the address points contains the pixel data of the drawing on the canvas.
```c++
// Obtain the pixel address after drawing. The memory to which the address points contains the pixel data of the drawing on the canvas.
The following samples are provided to help you better understand how to use the Native Drawing module:
*[2D Graphics Drawing Using Native Drawing](https://gitee.com/openharmony/graphic_graphic_2d/blob/master/rosen/samples/2d_graphics/drawing_c_sample.cpp)
*[Text Drawing and Painting Using Native Drawing](https://gitee.com/openharmony/graphic_graphic_2d/blob/master/rosen/samples/text/renderservice/drawing_text_c_sample.cpp)
