JAVA高级面试进阶训练营视频教程

admin

一、   问题描述

在页面使用PictureBox 加载资料图片后，点击“打印”，只能打印图片首页，较大图片则无法全部打印。

二、   原因分析

PictureBox中打印图片时没有设置继续打印相关属性，因此每次只能打印第1页。

三、解决方法

PictureBox控件增加打印全部页面属性，如果为True,表示打印全部页面；如果为False,保留原有逻辑不变。

在打印全部页面时，将控件的图片按页面大小切割，打印页面索引小于页面总数时，设置打印属性PrintPageEventArgs. HasMorePages = true继续打印，打印完成后将该属性设置为False结束打印。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Printing;
using System.Text;
using System.Windows.Forms;

namespace MyClass
{

    //public enum OperationState { Default, ZoomIn, ZoomOut };

    public partial class UCPictureBox : PictureBox
    {
        //private OperationState operationState;//处理状态
        private HScrollBar hScrollBar;//水平滚动条
        private VScrollBar vScrollBar;//垂直滚动条
        private PrintDocument printDocument;//打印对象
        private Rectangle currRect;//现在矩形对象
        private Bitmap currBmp;//现在图形对象
        //private int hScrollBarMidVal;//水平滚动条中间值
        //private int vScrollBarMidVal;//垂直滚动条中间值
        private RectangleF srcRect;
        private RectangleF destRect;
        private bool isMoveScrollBar;//是否移动滚动条        
        int currentPageIndex = 0;//当前页面
        int pageCount = 0;//打印页数
        
        /// <summary>
        /// 构造函数
        /// </summary>
        public UCPictureBox()
        {
            InitializeComponent();
            SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
            SetStyle(ControlStyles.AllPaintingInWmPaint, true);

            //hScrollBarMidVal = 0;
            //vScrollBarMidVal = 0;            
            //operationState = OperationState.Default;
            isMoveScrollBar = false;
            srcRect = new RectangleF();
            destRect = new RectangleF();
            printDocument = new PrintDocument();
            printDocument.PrintPage += new PrintPageEventHandler(printDocument_PrintPage);

            //构造水平滚动条
            hScrollBar = new HScrollBar();
            hScrollBar.Visible = false;
            hScrollBar.Dock = DockStyle.Bottom;
            hScrollBar.Scroll += new ScrollEventHandler(scrollBar_Scroll);
            this.Controls.Add(hScrollBar);

            //构造垂直滚动条
            vScrollBar = new VScrollBar();
            vScrollBar.Visible = false;
            vScrollBar.Dock = DockStyle.Right;
            vScrollBar.Scroll +=new ScrollEventHandler(scrollBar_Scroll);
            this.Controls.Add(vScrollBar);
        }

        #region 公共属性

        [Category("外观"), Description("获取或设置图片")]
        public new Image Image
        {
            get { return base.Image; }
            set
            {
                if (value != null)
                {
                    base.Image = value;
                    currRect.Width = base.Image.Width;
                    currRect.Height = base.Image.Height;
                    hScrollBar.Value = 0;
                    vScrollBar.Value = 0;
                    displayScrollBars();
                    setScrollBarsValues();
                    Invalidate();
                }
            }
        }

        //缩放比例
        private int scaleSize = 1;
        [Category("其它"), Description("获取或设置图片缩放比例")]
        public Int32 ScaleSize
        {
            get { return scaleSize; }
            set
            {
                if (value > 1 && value < 51)
                {
                    scaleSize = value;
                }
            }
        }

        //缩放倍数
        private int scaleScope = 5;
        [Category("其它"), Description("获取或设置图片最大缩放倍数")]
        public int ScaleScope
        {
            get { return scaleScope; }
            set
            {
                if (value > 1 && value < 11)
                {
                    scaleScope = value;
                }
            }
        }

        //图片边框颜色
        //private Color borderColor = Color.DarkGray;
        //[Category("其它"), Description("获取或设置图片边框颜色")]
        //public Color BorderColor
        //{
        //    get { return borderColor; }
        //    set { borderColor = value; }
        //}

        //图片边框宽度
        private int borderWidth = 5;
        [Category("其它"), Description("获取或设置图片边框宽度")]
        public Int32 BorderWidth
        {
            get { return borderWidth; }
            set { borderWidth = value; }
        }

        //打印全部页面
        [Category("其它"),Description("true-打印全部页面，false-打印首页")]
        public bool PrintAllPages { get; set; }

        #endregion

        #region 内部公共方法

        /// <summary>
        /// 从新绘制
        /// </summary>
        protected override void OnPaint(PaintEventArgs pe)
        {
            // TODO: 在此处添加自定义绘制代码
            // 调用基类 OnPaint
            base.OnPaint(pe);

            if (this.Image != null)
            {
                if (currBmp != null) { currBmp.Dispose(); }
                currBmp = new Bitmap(currRect.Width + 2 * borderWidth, currRect.Height + 2 * borderWidth);
                //绘制新图片
                using (Graphics g = Graphics.FromImage(currBmp))
                {
                    using (Pen pen = new Pen(BackColor, borderWidth))
                    {
                        g.DrawRectangle(pen, borderWidth * 0.5f, borderWidth * 0.5f,
                                        currRect.Width + borderWidth,
                                        currRect.Height + borderWidth);
                    }
                    g.DrawImage(this.Image, borderWidth, borderWidth, currRect.Width, currRect.Height);
                }

                //图片绘制到控件上
                pe.Graphics.Clear(BackColor);
                if (hScrollBar.Visible || vScrollBar.Visible)
                {//滚动条可见
                    drawDisplayedScrollBars(pe.Graphics);
                }
                else
                {//滚动条不可见
                    float x = 0, y = 0;
                    isMoveScrollBar = false;

                    //是否绘制到中心点坐标
                    if (this.SizeMode == PictureBoxSizeMode.CenterImage)
                    {
                        x = Math.Abs(ClientSize.Width - currBmp.Width) * 0.5f;
                        y = Math.Abs(ClientSize.Height - currBmp.Height) * 0.5f;
                    }
                    pe.Graphics.DrawImage(currBmp, x, y, currBmp.Width, currBmp.Height);
                }
            }
        }

        /// <summary>
        /// 重写控件大小发生改变事件
        /// </summary>
        protected override void OnClientSizeChanged(EventArgs e)
        {
            base.OnClientSizeChanged(e);
            displayScrollBars();
            setScrollBarsValues();
            Invalidate();
        }

        #endregion

        #region 图片打印与预览

        /// <summary>
        /// 打印图片
        /// </summary>
        public void PrintPictrue()
        {
            PrintDialog printDialog = new PrintDialog();
            printDialog.Document = printDocument;
            //added by lky 2017-11-16 修复Windows 7 x64位环境无法弹出打印对话框的问题
            printDialog.UseEXDialog = true;
            if (printDialog.ShowDialog() == DialogResult.OK)
            {
                try
                {
                    printDocument.Print();
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message, "打印出错", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    return;
                }
            }
        }

        /// <summary>
        /// 打印预览
        /// </summary>
        public void PrintPreview()
        {
            PrintPreviewDialog printPreviewDialog = new PrintPreviewDialog();
            printPreviewDialog.Document = printDocument;
            try
            {
                printPreviewDialog.ShowDialog();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "打印出错", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

        /// <summary>
        /// 打印图片事件
        /// </summary>
        private void printDocument_PrintPage(object sender, PrintPageEventArgs e)
        {
            if (currBmp == null)
                return;
            try
            {
                if (PrintAllPages)//added by lky 2018-1-15 打印全部页面
                {
                    int pageWith =(int) e.PageSettings.PrintableArea.Width;
                    int pageHeight = (int)e.PageSettings.PrintableArea.Height;
                    int horizontalTimes = (int)Math.Ceiling((decimal)currBmp.Width / pageWith);//水平方向切割页数
                    int verticalTimes = (int)Math.Ceiling((decimal)currBmp.Height / pageHeight);//垂直方向切割页数
                    if (pageCount == 0)
                    {
                        pageCount = horizontalTimes * verticalTimes;//总页数
                        currentPageIndex = 0;
                    }
                    int horizontalCurrentPosition = (currentPageIndex % horizontalTimes);//当前打印的水平偏移页数
                    int verticalCurrentPosition = (int)Math.Floor((decimal)currentPageIndex / horizontalTimes);//当前打印的垂直偏移页数
                    int x = horizontalCurrentPosition * pageWith;//水平方向打印偏移位置
                    int y = verticalCurrentPosition * pageHeight;//垂直方向打印偏移位置
                    int leftX = (currBmp.Width - x) > 0 ? (currBmp.Width - x) : 0;//水平方向未打印尺寸
                    int leftY = (currBmp.Height - y) > 0 ? (currBmp.Height - y) : 0;//垂直方向未打印尺寸

                    Bitmap printBmp = (Bitmap)currBmp.Clone(new Rectangle(x, y, (leftX > pageWith ? pageWith : leftX),
                        (leftY > pageHeight ? pageHeight : leftY)), currBmp.PixelFormat); //待打印图片缓存
                    e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
                    e.Graphics.PixelOffsetMode = PixelOffsetMode.HighSpeed;

                    e.Graphics.DrawImage(printBmp, 0, 0, printBmp.Width, printBmp.Height);
                    printBmp.Dispose();
                    currentPageIndex++;
                    e.HasMorePages = currentPageIndex < pageCount;//是否继续打印
                    if (!e.HasMorePages) pageCount = 0;//打印页数置为0
                }
                else //仅打印首页
                {
                    Bitmap printBmp = (Bitmap)currBmp.Clone(); 
                    e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
                    e.Graphics.PixelOffsetMode = PixelOffsetMode.HighSpeed;
                    e.Graphics.DrawImage(printBmp, 0, 0, printBmp.Width, printBmp.Height);
                    printBmp.Dispose();
                }
            }
            catch (Exception ex)
            {
                //写日志文件
                LogWriter.Write(LOG_CATEGORY.WIN_UI, LOG_LEVEL.ERROR, "UCPicturBox.PrintPage" + ex.ToString());
            }
        }

        #endregion

        #region 图片放大、缩小、原始大小、全屏显示、旋转功能

        /// <summary>
        /// 放大图片
        /// </summary>
        public void ZoomInPicture()
        {
            if (this.Image != null)
            {
                //operationState = OperationState.ZoomIn;
                double scale = 1 + (scaleSize * 0.01);
                currRect.Width = Convert.ToInt32(currRect.Width * scale);
                currRect.Height = currRect.Width * this.Image.Height / this.Image.Width;
                if (currRect.Width < (this.Image.Width * scaleScope))
                {                    
                    displayScrollBars();
                    setScrollBarsValues();
                    Invalidate();
                }
            }
        }

        /// <summary>
        /// 缩小图片
        /// </summary>
        public void ZoomOutPicture()
        {
            if (this.Image != null)
            {
                //operationState = OperationState.ZoomOut;
                double scale = 1 - (scaleSize * 0.01);
                currRect.Width = Convert.ToInt32(currRect.Width * scale);
                currRect.Height = currRect.Width * this.Image.Height / this.Image.Width;
                displayScrollBars();
                setScrollBarsValues();
                Invalidate();
            }
        }

        /// <summary>
        /// 原始大小
        /// </summary>
        public void ZoomOriginalPicture()
        {
            if (this.Image != null)
            {
                //operationState = OperationState.Default;
                isMoveScrollBar = false;
                currRect.Width = this.Image.Width;
                currRect.Height = this.Image.Height;
                displayScrollBars();
                setScrollBarsValues();
                Invalidate();
            }
        }

        /// <summary>
        /// 全屏显示
        /// </summary>
        public void ZoomShowAllPicture()
        {
            if (this.Image != null)
            {
                if (this.Image.Width > this.Image.Height)
                {
                    currRect.Width = ClientSize.Width - 2 * borderWidth;
                    currRect.Height = currRect.Width * this.Image.Height / this.Image.Width;
                    if ((currRect.Height + 2 * borderWidth) > ClientSize.Height)
                    {
                        currRect.Height = ClientSize.Height - 2 * borderWidth;
                        currRect.Width = currRect.Height * this.Image.Width / this.Image.Height;
                    }
                    //if ((currRect.Height + 2 * borderWidth) > ClientSize.Height)
                    //{
                    //    currRect.Width = ClientSize.Width - 2 * borderWidth - vScrollBar.Width;
                    //    currRect.Height = currRect.Width * this.Image.Height / this.Image.Width;
                    //}
                }
                else
                {
                    currRect.Height = ClientSize.Height - 2 * borderWidth;
                    currRect.Width = currRect.Height * this.Image.Width / this.Image.Height;
                    if ((currRect.Width + 2 * borderWidth) > ClientSize.Width)
                    {
                        currRect.Width = ClientSize.Width - 2 * borderWidth;
                        currRect.Height = currRect.Width * this.Image.Width / this.Image.Height;
                    }
                    //if ((currRect.Width + 2 * borderWidth) > ClientSize.Width)
                    //{
                    //    hScrollBar.Value = 0;
                    //    currRect.Height = ClientSize.Height - 2 * borderWidth - hScrollBar.Height;
                    //    currRect.Width = currRect.Height * this.Image.Width / this.Image.Height;
                    //}
                }
                isMoveScrollBar = false;
                displayScrollBars();
                setScrollBarsValues();
                Invalidate();
            }
        }

        /// <summary>
        /// 旋转图片
        /// </summary>
        public void RotatePicture()
        {
            if (this.Image != null)
            {
                isMoveScrollBar = false;
                this.Image.RotateFlip(RotateFlipType.Rotate90FlipNone);
                int tempWidth = currRect.Width;
                currRect.Width = currRect.Height;
                currRect.Height = tempWidth;
                displayScrollBars();
                setScrollBarsValues();
                Invalidate();
            }
        }

        /// <summary>
        /// 显示水平滚动条与垂直滚动条
        /// </summary>
        private void displayScrollBars()
        {
            //是否显示水平滚动条
            if ((currRect.Width + 2 * borderWidth) > ClientSize.Width)
            { hScrollBar.Visible = true; }
            else
            { hScrollBar.Visible = false; }

            //是否显示垂直滚动条
            if ((currRect.Height + 2 * borderWidth) > ClientSize.Height)
            { vScrollBar.Visible = true; }
            else
            { vScrollBar.Visible = false; }
        }

        /// <summary>
        /// 设置水平滚动条与垂直滚动条值
        /// </summary>
        private void setScrollBarsValues()
        {
            //设置水平滚动条值
            if (hScrollBar.Visible)
            {
                hScrollBar.Minimum = 0;
                hScrollBar.Maximum = currRect.Width - ClientSize.Width + 2 * borderWidth;
                hScrollBar.LargeChange = currRect.Width / 10;
                if (vScrollBar.Visible)
                {
                    hScrollBar.Maximum += vScrollBar.Width;
                }
                if (hScrollBar.LargeChange > hScrollBar.Maximum)
                {
                    hScrollBar.LargeChange = hScrollBar.Maximum - 1;
                }
                hScrollBar.SmallChange = hScrollBar.LargeChange / 5;
                hScrollBar.Maximum += hScrollBar.LargeChange;

                //绘制坐标为中心点
                if (this.SizeMode == PictureBoxSizeMode.CenterImage)
                {
                    if (hScrollBar.Value == 0 || isMoveScrollBar == false)
                    {
                        hScrollBar.Value = (hScrollBar.Maximum - hScrollBar.LargeChange) / 2;
                    }
                }
            }
            else
            { hScrollBar.Value = 0; }

            //设置垂直滚动条值
            if (vScrollBar.Visible)
            {
                vScrollBar.Minimum = 0;
                vScrollBar.Maximum = currRect.Height - ClientSize.Height + 2 * borderWidth;
                vScrollBar.LargeChange = currRect.Height / 10;
                if (hScrollBar.Visible)
                {
                    vScrollBar.Maximum += hScrollBar.Height;
                }
                if (vScrollBar.LargeChange > vScrollBar.Maximum)
                {
                    vScrollBar.LargeChange = vScrollBar.Maximum - 1;
                }
                vScrollBar.SmallChange = vScrollBar.LargeChange / 5;
                vScrollBar.Maximum += vScrollBar.LargeChange;

                //绘制坐标为中心点
                if (this.SizeMode == PictureBoxSizeMode.CenterImage)
                {
                    if (vScrollBar.Value == 0 || isMoveScrollBar ==false)
                    {                        
                        vScrollBar.Value = (vScrollBar.Maximum - vScrollBar.LargeChange) / 2;
                    }
                }
            }
            else
            { vScrollBar.Value = 0; }
        }

        /// <summary>
        /// 移动水平滚动条事件
        /// </summary>
        private void scrollBar_Scroll(object sender, ScrollEventArgs e)
        {
            isMoveScrollBar = true;
            using (Graphics graphics = this.CreateGraphics())
            {
                drawDisplayedScrollBars(graphics);
            }
            this.Update();
        }

        /// <summary>
        /// 从新绘制显示的滚动条
        /// </summary>
        private void drawDisplayedScrollBars(Graphics graphics)
        {
            float x = 0, y = 0;

            if (this.SizeMode == PictureBoxSizeMode.CenterImage)
            {
                x = Math.Abs(ClientSize.Width - currBmp.Width - vScrollBar.Width) * 0.5f;
                y = Math.Abs(ClientSize.Height - currBmp.Height - hScrollBar.Height) * 0.5f;
            }
            if (hScrollBar.Visible == false)
            {//水平滚动条不可见
                destRect.X = x;
                destRect.Y = 0;
                srcRect.X = 0;
                srcRect.Y = vScrollBar.Value;
            }
            else if (vScrollBar.Visible == false)
            {//垂直滚动条不可见
                destRect.X = 0;
                destRect.Y = y;
                srcRect.Y = 0;
                srcRect.X = hScrollBar.Value;
            }
            else
            {//两个滚动条都可见
                destRect.X = 0;
                destRect.Y = 0;
                srcRect.X = hScrollBar.Value;
                srcRect.Y = vScrollBar.Value;
            }
            destRect.Width = currBmp.Width;
            destRect.Height = currBmp.Height;
            srcRect.Width = currBmp.Width;
            srcRect.Height = currBmp.Height;
            graphics.DrawImage(currBmp, destRect, srcRect, GraphicsUnit.Pixel);
        }

        #endregion
    }
}