MuPDF Android Pdf 适合屏幕答案

【问题标题】：MuPDF Android Pdf fit to the screenMuPDF Android Pdf 适合屏幕
【发布时间】：2014-01-30 12:42:13
【问题描述】：

我为我的一款 Android 应用成功安装了 MuPDF。但问题是，在渲染时，我无法将 PDF 放到屏幕上。任何人都可以请建议我如何实现这一目标。谢谢！

【问题讨论】：

【解决方案1】：

编辑ReaderView.java中的measureView方法成为。

private void measureView(View v) {
        // See what size the view wants to be
        v.measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
        // Work out a scale that will fit it to this view
        float scale;
        if (getWidth()>getHeight())
        {
            scale = (float)getWidth()/(float)v.getMeasuredWidth();
            MIN_SCALE = (float)v.getMeasuredWidth()/(float)getWidth();
            MAX_SCALE = MIN_SCALE*5.0f;
        }
        else
            scale = Math.min((float)getWidth()/(float)v.getMeasuredWidth(),
                        (float)getHeight()/(float)v.getMeasuredHeight());

        // Use the fitting values scaled by our current scale factor
        v.measure(View.MeasureSpec.EXACTLY | (int)(v.getMeasuredWidth()*scale*mScale),
                View.MeasureSpec.EXACTLY | (int)(v.getMeasuredHeight()*scale*mScale));
    }

【讨论】：

这个解决方案的唯一问题是它不会正确地将初始 pdf 视图渲染到新的计算比例（它是为 1.0f 比例渲染的）。只有在进行了一些交互（触摸、平移、缩放）之后，它才会正确渲染。有什么方法可以强制初始渲染到新的比例？
这是一个老帖子，不能再扔了。

【解决方案2】：

我在 MAX 和 MIN 比例最终变量方面遇到了错误，但是我对 @hassan83 的解决方案进行了轻微修改。我的解决方案在 MuPDF 1.9a 版中进行了测试

private void measureView(View v) {
    // See what size the view wants to be
    v.measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
    // Work out a scale that will fit it to this view
    float scale;
    //landscape orientation
    if (getWidth() > getHeight())
    {
        scale = (float)getWidth()/(float)v.getMeasuredWidth() * (1.0f ); //make sure that we fill the page by multiplying with a scale factor of one
    }
    else
        scale = Math.min((float)getWidth()/(float)v.getMeasuredWidth(),
                (float)getHeight()/(float)v.getMeasuredHeight());

    // Use the fitting values scaled by our current scale factor
    v.measure(View.MeasureSpec.EXACTLY | (int)(v.getMeasuredWidth()*scale*mScale),
            View.MeasureSpec.EXACTLY | (int)(v.getMeasuredHeight()*scale*mScale));
}

【讨论】：

【解决方案3】：

这样，页面的大小从视图中引导过大。这是我的代码中的“measureview”方法：

    private void measureView(View v) {
    // See what size the view wants to be
    v.measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);

    if (!mReflow) {
        // Work out a scale that will fit it to this view
        float scale = Math.min((float) getWidth() / (float) v.getMeasuredWidth(),
                (float) getHeight() / (float) v.getMeasuredHeight());
        // Use the fitting values scaled by our current scale factor
        v.measure(MeasureSpec.AT_MOST | (int) (v.getMeasuredWidth() * (scale + 0.8f) * mScale),
                MeasureSpec.AT_MOST | (int) (v.getMeasuredHeight() * (scale+0.8f) * mScale));
    } else {
        v.measure(View.MeasureSpec.EXACTLY | (int) (v.getMeasuredWidth()),
                View.MeasureSpec.EXACTLY | (int) (v.getMeasuredHeight()));
    }
}

这是我需要的，启动页面需要在视图中准确获取，启动时文本可读。

【讨论】：

【解决方案4】：

除了回答https://stackoverflow.com/a/21168243/2982225，您可以通过在末尾添加以下代码来重新渲染视图：

requestLayout();
post(this);

再次。

所以完整的代码如下（最后评论前的代码归属地：the accepted answer of this question）：

private void measureView(View v) {
        // See what size the view wants to be
        v.measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
        // Work out a scale that will fit it to this view
        float scale;
        if (getWidth()>getHeight())
        {
            scale = (float)getWidth()/(float)v.getMeasuredWidth();
            MIN_SCALE = (float)v.getMeasuredWidth()/(float)getWidth();
            MAX_SCALE = MIN_SCALE*5.0f;
        }
        else
            scale = Math.min((float)getWidth()/(float)v.getMeasuredWidth(),
                        (float)getHeight()/(float)v.getMeasuredHeight());

        // Use the fitting values scaled by our current scale factor
        v.measure(View.MeasureSpec.EXACTLY | (int)(v.getMeasuredWidth()*scale*mScale),
                View.MeasureSpec.EXACTLY | (int)(v.getMeasuredHeight()*scale*mScale));

        // last comment
        // to force the initial rendering to the new scale

        requestLayout();
        post(this);
    }

希望这会有所帮助。

【讨论】：