java特粗宋体_JavaCV/javacpp opencv 结合freetype显示汉字

opencv 写中文到图片上网上有很多都是本地安装的然后配合freetype工作 javacv使用的是javacpp 不能用c/c++的直接解决方案，翻看了opencv的各个modules 发现在opencv_contrib的modules下有freetype这个模块

下载源码

然后 vim opencv/cppbuild.sh 找到找到并打开freetype模块的编译

BUILD_CONTRIB_X=".... -DBUILD_opencv_dnn_modern=OFF -DBUILD_opencv_freetype=ON-DBUILD_opencv_dpm=OFF -DBUILD_opencv_face=ON -DBUILD_opencv_hfs=OFF -DBUILD_opencv_latentsvm=OFF ....."

可能mvn仓库中没有SNAPSHOT的 javacpp 可以将源码一并clone下来然后手工编译

cd javacpp

mvn install -DskipTests

mvn install -DskipTests -pl .,opencv

然后会下载opencv的 c++版本库

等下载解压完用等mvn 编译完(需要很长时间) 下载玩完就可以先停掉 (机器好的可以忽略哈) 实际可能并没有编译freetype模块

下面有些细节

修改上面的cppbuild.sh 后 mvn构建会将freetype和harfbuzz加入构建

依赖 freetype harfbuzz 可以先 brew install freetype harfbuzz(maxos) 确保 freetype在待构建的列表中(如果本地没有安装freetype harfbuzz 很可能出现在 Unavaliable的列表里)

然后再下面的构建中可以看到

然而按照上面编译完成还是没法用freetype 因为没有添加java的接口

添加如下的映射类

javacpp-presets/opencv/src/main/java/org/bytedeco/javacpp/presets/opencv_freetype.java

package org.bytedeco.javacpp.presets;

import org.bytedeco.javacpp.annotation.Platform;

import org.bytedeco.javacpp.annotation.Properties;

import org.bytedeco.javacpp.tools.InfoMap;

import org.bytedeco.javacpp.tools.InfoMapper;

@Properties(

inherit = {opencv_core.class,opencv_imgproc.class},

value = {

@Platform(

include = {""},

link = "opencv_freetype@.3.4"

@Platform(value = "ios", preload = "libopencv_freetype"),

@Platform(value = "windows", link = "opencv_freetype342")

target = "org.bytedeco.javacpp.opencv_freetype"

)

public class opencv_freetype implements InfoMapper {

@Override public void map(InfoMap infoMap) {

}

后面会自动根据 freetype.cpp 接口文件生成 javacpp-presets/opencv/src/main/java/org/bytedeco/javacpp/presets/opencv_freetype.java 详细的方法映射文件(一开始我也以为要自己手写后面按照其他文件的方式随便写了一个可以编译的 mvn package的时候就被自动生成的给覆盖了应该不用自己写可以自动生成的)

Cpp 文件在javacpp-presets/opencv/cppbuild/macosx-x86_64/opencv_contrib-3.4.2/modules/freetype/include/opencv2/freetype.hpp

这个接口文件可以看下

namespace cv {

namespace freetype {

//! @addtogroup freetype

//! @{

class CV_EXPORTS_W FreeType2 : public Algorithm

{

public:

/** @brief Load font data.

The function loadFontData loads font data.

@param fontFileName FontFile Name

@param id face_index to select a font faces in a single file.

CV_WRAP virtual void loadFontData(String fontFileName, int id) = 0;

/** @brief Set Split Number from Bezier-curve to line

The function setSplitNumber set the number of split points from bezier-curve to line.

If you want to draw large glyph, large is better.

If you want to draw small glyph, small is better.

@param num number of split points from bezier-curve to line

CV_WRAP virtual void setSplitNumber( int num ) = 0;

/** @brief Draws a text string. 核心的就是这个可以写UTF编码的默认opencv_imgproc.putText只能写ascii码

The function putText renders the specified text string in the image. Symbols that cannot be rendered using the specified font are replaced by "Tofu" or non-drawn.

@param img Image.

@param text Text string to be drawn.

@param org Bottom-left/Top-left corner of the text string in the image.

@param fontHeight Drawing font size by pixel unit.

@param color Text color.

@param thickness Thickness of the lines used to draw a text when negative, the glyph is filled. Otherwise, the glyph is drawn with this thickness.

@param line_type Line type. See the line for details.

@param bottomLeftOrigin When true, the image data origin is at the bottom-left corner. Otherwise, it is at the top-left corner.

CV_WRAP virtual void putText(

InputOutputArray img, const String& text, Point org,

int fontHeight, Scalar color,

int thickness, int line_type, bool bottomLeftOrigin

) = 0;

/** @brief Calculates the width and height of a text string.

The function getTextSize calculates and returns the approximate size of a box that contains the specified text.

That is, the following code renders some text, the tight box surrounding it, and the baseline: :

@code

String text = "Funny text inside the box";

int fontHeight = 60;

int thickness = -1;

int linestyle = 8;

Mat img(600, 800, CV_8UC3, Scalar::all(0));

int baseline=0;

cv::Ptr<:freetype::freetype2> ft2;

ft2 = cv::freetype::createFreeType2();

ft2->loadFontData( "./mplus-1p-regular.ttf", 0 );

Size textSize = ft2->getTextSize(text,

fontHeight,

thickness,

&baseline);

if(thickness > 0){

baseline += thickness;

}

// center the text

Point textOrg((img.cols - textSize.width) / 2,

(img.rows + textSize.height) / 2);

// draw the box

rectangle(img, textOrg + Point(0, baseline),

textOrg + Point(textSize.width, -textSize.height),

Scalar(0,255,0),1,8);

// ... and the baseline first

line(img, textOrg + Point(0, thickness),

textOrg + Point(textSize.width, thickness),

Scalar(0, 0, 255),1,8);

// then put the text itself

ft2->putText(img, text, textOrg, fontHeight,

Scalar::all(255), thickness, linestyle, true );

@endcode

@param text Input text string.

@param fontHeight Drawing font size by pixel unit.

@param thickness Thickness of lines used to render the text. See putText for details.

@param[out] baseLine y-coordinate of the baseline relative to the bottom-most text

point.

@return The size of a box that contains the specified text.

@see cv::putText

CV_WRAP virtual Size getTextSize(const String& text,

int fontHeight, int thickness,

CV_OUT int* baseLine) = 0;

};

/** @brief Create FreeType2 Instance

The function createFreeType2 create instance to draw UTF-8 strings.

CV_EXPORTS_W Ptr createFreeType2();

//! @}

} } // namespace freetype

#endif

生成的java文件是这样的 javacpp-presets/opencv/src/main/java/org/bytedeco/javacpp/opencv_freetype.java

// Targeted by JavaCPP version 1.4.3-SNAPSHOT: DO NOT EDIT THIS FILE

package org.bytedeco.javacpp;

import java.nio.*;

import org.bytedeco.javacpp.*;

import org.bytedeco.javacpp.annotation.*;

import static org.bytedeco.javacpp.opencv_core.*;

import static org.bytedeco.javacpp.opencv_imgproc.*;

public class opencv_freetype extends org.bytedeco.javacpp.presets.opencv_freetype {

static { Loader.load(); }

// Parsed from

//################################################################################

// Created by Kumataro

//################################################################################

// #ifndef _OPENCV_FREETYPE_H_

// #define _OPENCV_FREETYPE_H_

// #ifdef __cplusplus

// #include

/**

\defgroup freetype Drawing UTF-8 strings with freetype/harfbuzz

This modules is to draw UTF-8 strings with freetype/harfbuzz.

1. Install freetype2 and harfbuzz in your system.

2. Create FreeType2 instance with createFreeType2() function.

3. Load font file with loadFontData() function.

4. Draw text with putText() function.

- If thickness parameter is negative, drawing glyph is filled.

- If thickness parameter is positive, drawing glyph is outlined with thickness.

- If line_type parameter is 16(or CV_AA), drawing glyph is smooth.

/** \addtogroup freetype

* \{ */

@Namespace("cv::freetype") public static class FreeType2 extends Algorithm {

static { Loader.load(); }

/** Pointer cast constructor. Invokes {@link Pointer#Pointer(Pointer)}. */

public FreeType2(Pointer p) { super(p); }

/** \brief Load font data.

The function loadFontData loads font data.

@param fontFileName FontFile Name

@param id face_index to select a font faces in a single file.

public native void loadFontData(@Str BytePointer fontFileName, int id);

public native void loadFontData(@Str String fontFileName, int id);

/** \brief Set Split Number from Bezier-curve to line

The function setSplitNumber set the number of split points from bezier-curve to line.

If you want to draw large glyph, large is better.

If you want to draw small glyph, small is better.

@param num number of split points from bezier-curve to line

public native void setSplitNumber( int num );

/** \brief Draws a text string.

The function putText renders the specified text string in the image. Symbols that cannot be rendered using the specified font are replaced by "Tofu" or non-drawn.

@param img Image.

@param text Text string to be drawn.

@param org Bottom-left/Top-left corner of the text string in the image.

@param fontHeight Drawing font size by pixel unit.

@param color Text color.

@param thickness Thickness of the lines used to draw a text when negative, the glyph is filled. Otherwise, the glyph is drawn with this thickness.

@param line_type Line type. See the line for details.

@param bottomLeftOrigin When true, the image data origin is at the bottom-left corner. Otherwise, it is at the top-left corner.

public native void putText(

@ByVal Mat img, @Str BytePointer text, @ByVal Point org,

int fontHeight, @ByVal Scalar color,

int thickness, int line_type, @Cast("bool") boolean bottomLeftOrigin

);

public native void putText(

@ByVal Mat img, @Str String text, @ByVal Point org,

int fontHeight, @ByVal Scalar color,

int thickness, int line_type, @Cast("bool") boolean bottomLeftOrigin

);

public native void putText(

@ByVal UMat img, @Str String text, @ByVal Point org,

int fontHeight, @ByVal Scalar color,

int thickness, int line_type, @Cast("bool") boolean bottomLeftOrigin

);

public native void putText(

@ByVal UMat img, @Str BytePointer text, @ByVal Point org,

int fontHeight, @ByVal Scalar color,

int thickness, int line_type, @Cast("bool") boolean bottomLeftOrigin

);

public native void putText(

@ByVal GpuMat img, @Str BytePointer text, @ByVal Point org,

int fontHeight, @ByVal Scalar color,

int thickness, int line_type, @Cast("bool") boolean bottomLeftOrigin

);

public native void putText(

@ByVal GpuMat img, @Str String text, @ByVal Point org,

int fontHeight, @ByVal Scalar color,

int thickness, int line_type, @Cast("bool") boolean bottomLeftOrigin

);

/** \brief Calculates the width and height of a text string.

The function getTextSize calculates and returns the approximate size of a box that contains the specified text.

That is, the following code renders some text, the tight box surrounding it, and the baseline: :

{@code

String text = "Funny text inside the box";

int fontHeight = 60;

int thickness = -1;

int linestyle = 8;

Mat img(600, 800, CV_8UC3, Scalar::all(0));

int baseline=0;

cv::Ptr<:freetype::freetype2> ft2;

ft2 = cv::freetype::createFreeType2();

ft2->loadFontData( "./mplus-1p-regular.ttf", 0 );

Size textSize = ft2->getTextSize(text,

fontHeight,

thickness,

&baseline);

if(thickness > 0){

baseline += thickness;

}

// center the text

Point textOrg((img.cols - textSize.width) / 2,

(img.rows + textSize.height) / 2);

// draw the box

rectangle(img, textOrg + Point(0, baseline),

textOrg + Point(textSize.width, -textSize.height),

Scalar(0,255,0),1,8);

// ... and the baseline first

line(img, textOrg + Point(0, thickness),

textOrg + Point(textSize.width, thickness),

Scalar(0, 0, 255),1,8);

// then put the text itself

ft2->putText(img, text, textOrg, fontHeight,

Scalar::all(255), thickness, linestyle, true );

}

@param text Input text string.

@param fontHeight Drawing font size by pixel unit.

@param thickness Thickness of lines used to render the text. See putText for details.

@param [out] baseLine y-coordinate of the baseline relative to the bottom-most text

point.

@return The size of a box that contains the specified text.

@see cv::putText

public native @ByVal Size getTextSize(@Str BytePointer text,

int fontHeight, int thickness,

IntPointer baseLine);

public native @ByVal Size getTextSize(@Str String text,

int fontHeight, int thickness,

IntBuffer baseLine);

public native @ByVal Size getTextSize(@Str BytePointer text,

int fontHeight, int thickness,

int[] baseLine);

public native @ByVal Size getTextSize(@Str String text,

int fontHeight, int thickness,

IntPointer baseLine);

public native @ByVal Size getTextSize(@Str BytePointer text,

int fontHeight, int thickness,

IntBuffer baseLine);

public native @ByVal Size getTextSize(@Str String text,

int fontHeight, int thickness,

int[] baseLine);

}

/** \brief Create FreeType2 Instance

The function createFreeType2 create instance to draw UTF-8 strings.

@Namespace("cv::freetype") public static native @Ptr FreeType2 createFreeType2();

/** \} */

// namespace freetype

// #endif

}

编译完成后可以看到最终的 opencv-3.4.2-1.4.3-SNAPSHOT-macosx-x86_64.jar 文件里面多了一个

/org/bytedeco/javacpp/macosx-x86_64/libopencv_freetype.3.4.dylib

按照下面调用API即可

FreeType2 ft2 = opencv_freetype.createFreeType2();

//需要载入一个一种中午的字体这里是宋体

ft2.loadFontData("src/main/resources/ttf/Songti.ttc", 0);

ft2.setSplitNumber(1);

ft2.putText(mat, //图片

label, //文字

new Point(100，100), //开始的位置

18, //大小单位是px

Scalar.BLACK, //颜色

1, //thickness 粗细

opencv_core.LINE_4, //线条类型

false); //bottomLeftOrigin=true

原文链接：https://blog.csdn.net/weixin_30624767/article/details/114512286