tools/util/image/image.go

package image

import (
	"fmt"
	"gopkg.in/gographics/imagick.v3/imagick"
	"icloudapp.cn/tools/util"
	fileObj "icloudapp.cn/tools/util/file"
)

type Image struct {
	Basic
	Path string
}

// NewImage 创建新的Image对象
func NewImage(path string) *Image {
	ImageInstance := &Image{
		Path: path,
	}
	//初始化指针相关数据，避免使用时nil了
	ImageInstance.SetSize(0, 0)
	ImageInstance.SetPoint(0, 0)
	return ImageInstance
}

// Create 创建图像
func (i *Image) Create() (*imagick.MagickWand, error) {
	if i.ViewSize.Width == 0 || i.ViewSize.Height == 0 {
		return nil, util.NewError("Create Text", "指定元素未设置长宽")
	}
	if i.File != "" {
		i.File = fmt.Sprintf("%s/%s", i.Path, i.File)
		if !fileObj.IsFile(i.File) {
			return nil, util.NewError(fmt.Sprintf("文件 %s 不存在", i.File))
		}
	}
	imageMW := imagick.NewMagickWand()

	if i.File != "" {
		if err := imageMW.ReadImage(i.File); err != nil {
			return nil, util.NewError(fmt.Sprintf("imageMW.ReadImageBlob:%s", err.Error()))
		}
		if err := imageMW.ResizeImage(i.ViewSize.Width, i.ViewSize.Height, imagick.FILTER_LANCZOS); err != nil {
			return nil, util.NewError(fmt.Sprintf("imageMW.ResizeImage:%s", err.Error()))
		}
	} else {
		if err := imageMW.NewImage(i.ViewSize.Width, i.ViewSize.Height, OpacityPixel()); err != nil {
			return nil, util.NewError(fmt.Sprintf("imageMW.NewImage:%s", err.Error()))
		}
	}
	if err := imageMW.SetImageFormat("PNG"); err != nil {
		return nil, util.NewError("imageMW.SetImageFormat", err.Error())
	}

	if i.Background != "" {
		if err := imageMW.SetImageBackgroundColor(Pixel(i.Background)); err != nil {
			return nil, util.NewError(fmt.Sprintf("imageMW.SetImageBackgroundColor:%s", err.Error()))
		}
	}
	if i.Angle > 0 {
		if err := imageMW.RotateImage(OpacityPixel(), i.Angle); err != nil {
			return nil, util.NewError(fmt.Sprintf("imageMW.RotateImage:%s", err.Error()))
		}
		fmt.Println("imageMW.GetImageWidth", imageMW.GetImageWidth(), i.ViewSize.Width, imageMW.GetImageHeight(), i.ViewSize.Height)
		alignX := float64(imageMW.GetImageWidth()-i.ViewSize.Width) / 2
		alignY := float64(imageMW.GetImageHeight()-i.ViewSize.Height) / 2
		i.SetPoint(i.ViewPoint.X-alignX, i.ViewPoint.Y-alignY)
	}
	return imageMW, nil
}

// Thumb 生成缩略图
func (i *Image) Thumb() (*imagick.MagickWand, error) {
	if !fileObj.IsFile(i.File) {
		return nil, util.NewError(fmt.Sprintf("文件 %s 不存在", i.File))
	}

	mw := imagick.NewMagickWand()

	var err error

	if err = mw.ReadImage(i.File); err != nil {
		return nil, util.NewError("mw.ReadImage err :", err.Error())
	}

	width := mw.GetImageWidth()
	height := mw.GetImageHeight()

	imageScale := NewScale(width, height, 1.0)
	scale := imageScale.MinRatio(i.ViewSize.Width, i.ViewSize.Height)

	if err = mw.ResizeImage(scale.Width, scale.Height, imagick.FILTER_LANCZOS); err != nil {
		return nil, util.NewError("mw.ResizeImage err :", err.Error())
	}
	return mw, nil
}

// Cut 裁切图片，先将图片进行按最大比例缩放后再裁切，使裁切的图片显示更多内容
func (i *Image) Cut(position string) (*imagick.MagickWand, error) {
	if position == "" {
		position = "left"
	}

	mw := imagick.NewMagickWand()

	if err := mw.ReadImage(i.File); err != nil {
		return nil, util.NewError("mw.ReadImage err : ", err.Error())
	}
	sourceWidth := mw.GetImageWidth()
	sourceHeight := mw.GetImageHeight()
	imageScale := NewScale(sourceWidth, sourceHeight, 1.0)

	scale := imageScale.MaxRatio(i.ViewSize.Width, i.ViewSize.Height)

	if err := mw.ResizeImage(scale.Width, scale.Height, imagick.FILTER_LANCZOS); err != nil {
		return nil, util.NewError("mw.ResizeImage err : ", err.Error())
	}
	x, y, width, height := i.Position(position, scale.Width, scale.Height, i.ViewSize)

	if err := mw.CropImage(width, height, x, y); err != nil {
		return nil, util.NewError("mw.CropImage err : ", err.Error())
	}
	return mw, nil
}

// Resize 缩放
func (i *Image) Resize() (*imagick.MagickWand, error) {
	imageMV := imagick.NewMagickWand()

	if err := imageMV.ReadImage(i.File); err != nil {
		return nil, util.NewError("Resize", "ReadImage", err.Error())
	}

	if err := imageMV.ResizeImage(i.ViewSize.Width, i.ViewSize.Height, imagick.FILTER_LANCZOS); err != nil {
		return nil, util.NewError("Resize", "ResizeImage", err.Error())
	}
	/*
		if err := imageMV.SetSize(i.ViewSize.Width, i.ViewSize.Height); err != nil {
			return nil, util.NewError("Resize", "SetSize", err.Error())
		}
	*/
	if i.Angle > 0 {
		if err := imageMV.RotateImage(OpacityPixel(), i.Angle); err != nil {
			return nil, util.NewError("Resize", "ResizeImage", err.Error())
		}
		alignX := float64(imageMV.GetImageWidth()-i.ViewSize.Width) / 2
		alignY := float64(imageMV.GetImageHeight()-i.ViewSize.Height) / 2
		i.ViewPoint.X = alignX
		i.ViewPoint.Y = alignY
	}
	return imageMV, nil
}