Native Drawing开发指导，实现HarmonyOS基本图形和字体的绘制 原创

// 创建一个bitmap对象
OH_Drawing_Bitmap* cBitmap = OH_Drawing_BitmapCreate();
// 定义bitmap的像素格式
OH_Drawing_BitmapFormat cFormat {COLOR_FORMAT_RGBA_8888, ALPHA_FORMAT_OPAQUE};
// 构造对应格式的bitmap
OH_Drawing_BitmapBuild(cBitmap, width, height, &cFormat);
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// 创建一个canvas对象
OH_Drawing_Canvas* cCanvas = OH_Drawing_CanvasCreate();
// 将画布与bitmap绑定，画布画的内容会输出到绑定的bitmap内存中
OH_Drawing_CanvasBind(cCanvas, cBitmap);
// 使用白色清除画布内容
OH_Drawing_CanvasClear(cCanvas, OH_Drawing_ColorSetArgb(0xFF, 0xFF, 0xFF, 0xFF));
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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;

// 创建一个path对象，然后使用接口连接成一个五角星形状
OH_Drawing_Path* cPath = OH_Drawing_PathCreate();
// 指定path的起始位置
OH_Drawing_PathMoveTo(cPath, aX, aY);
// 用直线连接到目标点
OH_Drawing_PathLineTo(cPath, bX, bY);
OH_Drawing_PathLineTo(cPath, cX, cY);
OH_Drawing_PathLineTo(cPath, dX, dY);
OH_Drawing_PathLineTo(cPath, eX, eY);
// 闭合形状，path绘制完毕
OH_Drawing_PathClose(cPath);
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// 创建一个画笔Pen对象，Pen对象用于形状的边框线绘制
OH_Drawing_Pen* cPen = OH_Drawing_PenCreate();
OH_Drawing_PenSetAntiAlias(cPen, true);
OH_Drawing_PenSetColor(cPen, OH_Drawing_ColorSetArgb(0xFF, 0xFF, 0x00, 0x00));
OH_Drawing_PenSetWidth(cPen, 10.0);
OH_Drawing_PenSetJoin(cPen, LINE_ROUND_JOIN);
// 将Pen画笔设置到canvas中
OH_Drawing_CanvasAttachPen(cCanvas, cPen);

// 创建一个画刷Brush对象，Brush对象用于形状的填充
OH_Drawing_Brush* cBrush = OH_Drawing_BrushCreate();
OH_Drawing_BrushSetColor(cBrush, OH_Drawing_ColorSetArgb(0xFF, 0x00, 0xFF, 0x00));

// 将Brush画刷设置到canvas中
OH_Drawing_CanvasAttachBrush(cCanvas, cBrush);
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// 在画布上画path的形状，五角星的边框样式为pen设置，颜色填充为Brush设置
OH_Drawing_CanvasDrawPath(cCanvas, cPath);
// 销毁创建的对象
OH_Drawing_BrushDestroy(cBrush);
OH_Drawing_PenDestroy(cPen);
OH_Drawing_PathDestroy(cPath);
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// 画完后获取像素地址，地址指向的内存包含画布画的像素数据
void* bitmapAddr = OH_Drawing_BitmapGetPixels(cBitmap);
std::copy(addr, addr + addrSize, static_cast<uint8_t*>(bitmapAddr));
// 销毁canvas对象
OH_Drawing_CanvasDestroy(cCanvas);
// 销毁bitmap对象
OH_Drawing_BitmapDestroy(cBitmap);
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// 创建bitmap
OH_Drawing_Bitmap* cBitmap = OH_Drawing_BitmapCreate();
OH_Drawing_BitmapFormat cFormat {COLOR_FORMAT_RGBA_8888, ALPHA_FORMAT_OPAQUE};
OH_Drawing_BitmapBuild(cBitmap, width, height, &cFormat);
// 创建canvas
OH_Drawing_Canvas* cCanvas = OH_Drawing_CanvasCreate();
OH_Drawing_CanvasBind(cCanvas, cBitmap);
OH_Drawing_CanvasClear(cCanvas, OH_Drawing_ColorSetArgb(0xFF, 0xFF, 0xFF, 0xFF));
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// 选择从左到右/左对齐等排版属性
OH_Drawing_TypographyStyle* typoStyle = OH_Drawing_CreateTypographyStyle();
OH_Drawing_SetTypographyTextDirection(typoStyle, TEXT_DIRECTION_LTR);
OH_Drawing_SetTypographyTextAlign(typoStyle, TEXT_ALIGN_LEFT);
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// 设置文字颜色，例如黑色
OH_Drawing_TextStyle* txtStyle = OH_Drawing_CreateTextStyle();
OH_Drawing_SetTextStyleColor(txtStyle, OH_Drawing_ColorSetArgb(0xFF, 0x00, 0x00, 0x00));
// 设置文字大小、字重等属性
double fontSize = 30;
OH_Drawing_SetTextStyleFontSize(txtStyle, fontSize);
OH_Drawing_SetTextStyleFontWeight(txtStyle, FONT_WEIGHT_400);
OH_Drawing_SetTextStyleBaseLine(txtStyle, TEXT_BASELINE_ALPHABETIC);
OH_Drawing_SetTextStyleFontHeight(txtStyle, 1);
// 设置字体类型等
const char* fontFamilies[] = {"Roboto"};
OH_Drawing_SetTextStyleFontFamilies(txtStyle, 1, fontFamilies);
OH_Drawing_SetTextStyleFontStyle(txtStyle, FONT_STYLE_NORMAL);
OH_Drawing_SetTextStyleLocale(txtStyle, "en");
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OH_Drawing_TypographyCreate* handler = OH_Drawing_CreateTypographyHandler(typoStyle,
    OH_Drawing_CreateFontCollection());
OH_Drawing_TypographyHandlerPushTextStyle(handler, txtStyle);
// 设置文字内容
const char* text = "HarmonyOS\n";
OH_Drawing_TypographyHandlerAddText(handler, text);
OH_Drawing_TypographyHandlerPopTextStyle(handler);
OH_Drawing_Typography* typography = OH_Drawing_CreateTypography(handler);
// 设置页面最大宽度
double maxWidth = 800.0;
OH_Drawing_TypographyLayout(typography, maxWidth);
// 设置文本在画布上绘制的起始位置
double position[2] = {10.0, 15.0};
// 将文本绘制到画布上
OH_Drawing_TypographyPaint(typography, cCanvas, position[0], position[1]);
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