使用 ImageGetter 在 textview 中缩放图像

Question

我正在尝试缩放文本视图中显示的图像，但我不能。

我正在使用此代码，但无论如何，它都会显示在容器内裁剪的图像或根本不显示。

int width, height;
DisplayMetrics metrics = new DisplayMetrics();
metrics = Resources.getSystem().getDisplayMetrics();

int originalWidthScaled = (int) (result.getIntrinsicWidth() * metrics.density);
            int originalHeightScaled = (int) (result.getIntrinsicHeight() * metrics.density);
            if (originalWidthScaled > metrics.widthPixels) {
                height = result.getIntrinsicHeight() * metrics.widthPixels
                        / result.getIntrinsicWidth();
                width = metrics.widthPixels;
            } else {
                height = originalHeightScaled;
                width = originalWidthScaled;
            }
                urlDrawable.drawable = result; 

                urlDrawable.setBounds(0, 0, 0+width, 0+height);

                // change the reference of the current drawable to the result 
                // from the HTTP call 

                // redraw the image by invalidating the container 

                container.invalidate();

                // For ICS
                container.setHeight(
                        container.getHeight() + 
                        result.getIntrinsicHeight());

                // Pre ICS
                container.setEllipsize(null);

Answer 1

我回答自己我变了

 if (originalWidthScaled > metrics.widthPixels) {
                height = result.getIntrinsicHeight() * metrics.widthPixels
                        / result.getIntrinsicWidth();
                width = metrics.widthPixels;
            }

为

if (originalWidthScaled > (metrics.widthPixels * 70) / 100) {
                width = (metrics.widthPixels * 70) / 100;

                height = result.getIntrinsicHeight() * width
                        / result.getIntrinsicWidth();
            }

现在它占据了屏幕空间的 70%，正好是容器的最大尺寸

Answer 2

对于仍在使用新 API 寻找答案的任何人，ImageGetter 的此自定义实现应该允许您放大将占据设备显示宽度的图像，如果给定图像大于设备显示则缩小宽度或保留其原始尺寸（如果更小）。

/**
 * Custom ImageGetter for [HtmlCompat.fromHtml] which accept both Url and Base64 from img tag.
 * */
class HtmlImageGetter(
    private val scope: LifecycleCoroutineScope,
    private val res: Resources,
    private val glide: RequestManager,
    private val htmlTextView: AppCompatTextView,
    @DrawableRes
    private val errorImage: Int = 0,
    private val matchParent: Boolean = true
) : ImageGetter {

    override fun getDrawable(source: String): Drawable {
        val holder = BitmapDrawablePlaceHolder(res, null)

        scope.launch(Dispatchers.IO) {
            runCatching {

                glide
                    .asBitmap()
                    .load(
                        if (source.matches(Regex("data:image.*base64.*")))
                            Base64.decode(
                                source.replace("data:image.*base64".toRegex(), ""),
                                Base64.DEFAULT
                            ) // Image tag used Base64
                        else
                            source // Image tag used URL
                    )
                    .submit()
                    .get()

            }
                .onSuccess { setDrawable(holder, it) }
                .onFailure {

                    if (errorImage != 0)
                        BitmapFactory.decodeResource(res, errorImage)?.let {
                            setDrawable(holder, it)
                        }

                }
        }

        return holder
    }

    private suspend fun setDrawable(holder: BitmapDrawablePlaceHolder, bitmap: Bitmap) {
        val drawable = BitmapDrawable(res, bitmap)

        val width: Int
        val height: Int

        val metrics = res.displayMetrics
        val displayWidth = metrics.widthPixels - (htmlTextView.paddingStart + htmlTextView.paddingEnd + htmlTextView.marginStart + htmlTextView.marginEnd) * 100 / 100

        val imageWidthScaled = (drawable.intrinsicWidth * metrics.density)
        val imageHeightScaled = (drawable.intrinsicHeight * metrics.density)

        // Scale up if matchParent is true
        // Scale down if matchParent is false
        if (matchParent || imageWidthScaled > displayWidth) {
            width = displayWidth
            height = (drawable.intrinsicHeight * width / drawable.intrinsicWidth)
        }
        else {
            height = imageHeightScaled.roundToInt()
            width = imageWidthScaled.roundToInt()
        }

        drawable.setBounds(0, 0, width, height)

        holder.setDrawable(drawable)
        holder.setBounds(0, 0, width, height)

        withContext(Dispatchers.Main) { htmlTextView.text = htmlTextView.text }
    }

    internal class BitmapDrawablePlaceHolder(res: Resources, bitmap: Bitmap?) :
        BitmapDrawable(res, bitmap) {
        private var drawable: Drawable? = null

        override fun draw(canvas: Canvas) {
            drawable?.run { draw(canvas) }
        }

        fun setDrawable(drawable: Drawable) {
            this.drawable = drawable
        }
    }
}