如何将 GIF 动画播放到最后一帧，然后停止动画？

Question

在我的项目中，我想在 PictureBox 中播放 GIF。
我需要播放 GIF 动画包含的所有帧，然后停止动画。

我正在使用 ImageAnimator class 为 GIF 图片制作动画，我只是不知道如何停止它。

Private image As Image = My.Resources.icon_confirmation
'Private frames As Integer
Dim FDimensions As System.Drawing.Imaging.FrameDimension = New System.Drawing.Imaging.FrameDimension(image.FrameDimensionsList(0))
Dim frames As Integer = image.GetFrameCount(FDimensions)

Private Sub paintFrame(ByVal sender As Object, ByVal e As EventArgs)
    If frames < 33 Then PictureBox1.Image = image Else ImageAnimator.StopAnimate(image, AddressOf StopAnim)
End Sub

Private Sub StopAnim(ByVal sender As Object, ByVal e As EventArgs)
    PictureBox1.Dispose()
End Sub

Private Sub PictureBox1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles PictureBox1.Paint
    If frames = 12 Then
        ImageAnimator.UpdateFrames()
        e.Graphics.DrawImage(image, Point.Empty)
        frames -= 1
    End If
End Sub

Answer 1

要跟踪在 PictureBox 上绘制的当前帧，您需要一个字段来存储当前进度并将其与动画包含的帧数进行比较。

当进度到达最后一帧（或最后一帧之前的任何其他帧，无论需要什么），您停止动画调用 ImageAnimator.StopAnimate()。

要启动动画，您首先检查是否ImageAnimator.CanAnimate() (it may not be able to animate the Image you specified). If it can, then you call ImageAnimator.Animate()，向方法传递图像对象和处理FrameChanged事件的方法的地址。

此处理程序用于检查动画是否应继续。如果满足所有条件（不是所有的 Frames 都被绘制），Invalidate() the Control used to show the animation and, in its Paint event handler, call ImageAnimator.UpdateFrames() to change the current Frame, then e.Graphics.DrawImage() 绘制 Image（绘制当前的 Frame）。

▶ 正如您在可视化示例中所见，我使用按钮 (btnAnimate) 启动动画。如果愿意，您可以将该代码移至 Form.Shown 事件处理程序。
▶ 我添加了一个循环计数器，以防动画循环不止一次。

这是它的视觉效果：

Imports System.Drawing.Imaging
' [...]

Private animation As Image = My.Resources.icon_confirmation
Private animationFrames As Integer = 0
Private currentFrame As Integer = 0
Private animationMaxLoops As Integer = 1
Private loops As Integer = 0

Private Sub btnAnimate_Click(sender As Object, e As EventArgs) Handles btnAnimate.Click
    animationFrames = animation.GetFrameCount(New FrameDimension(animation.FrameDimensionsList(0)))
    AnimateImage()
End Sub

Public Sub AnimateImage()
    If ImageAnimator.CanAnimate(animation) Then
        ImageAnimator.Animate(animation, AddressOf OnFrameChanged)
    End If
End Sub

Private Sub OnFrameChanged(o As Object, e As EventArgs)
    If currentFrame >= animationFrames Then
        currentFrame = 0
        loops += 1
        If loops >= animationMaxLoops Then
            animationFrames = 0
            loops = 0
            ImageAnimator.StopAnimate(animation, AddressOf OnFrameChanged)
        End If
    Else
        pictureBox1.Invalidate()
        currentFrame += 1
    End If
End Sub

Private Sub pictureBox1_Paint(sender As Object, e As PaintEventArgs) Handles pictureBox1.Paint
    If animationFrames > 0 Then
        ImageAnimator.UpdateFrames()
        e.Graphics.DrawImage(animation, Point.Empty)
    End If
End Sub

C#版本

private Image animation = Properties.Resources.Some_GIF_Image;
private int animationFrames = 0;
private int currentFrame = 0;
private int animationMaxLoops = 1;
private int loops = 0;


private void btnAnimate_Click(object sender, EventArgs e)
{
    animationFrames = animation.GetFrameCount(new FrameDimension(animation.FrameDimensionsList[0]));
    AnimateImage();
}

private void AnimateImage()
{
    if (ImageAnimator.CanAnimate(animation)) {
        ImageAnimator.Animate(animation, OnFrameChanged);
    }
}

private void OnFrameChanged(object sender, EventArgs e)
{
    if (currentFrame >= animationFrames) {
        currentFrame = 0;
        loops += 1;
        if (loops >= animationMaxLoops) {
            animationFrames = 0;
            loops = 0;
            ImageAnimator.StopAnimate(animation, OnFrameChanged);
        }
    }
    else {
        pictureBox1.Invalidate();
        currentFrame += 1;
    }
}

private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
    if (animationFrames > 0)  {
        ImageAnimator.UpdateFrames();
        e.Graphics.DrawImage(animation, Point.Empty);
    }
}

A PasteBin of a complete Form 使用项目资源中的图像执行动画。

如何将 GIF 动画播放到最后一帧，然后停止动画？

How to play a GIF animation to the last Frame, then stop the animation?

vb.net

graphics

animated-gif

picturebox

winforms