NosThumbImageUtil.java

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package com.netease.nimlib.sdk.nos.util;

import android.util.DisplayMetrics;

import com.netease.nimlib.SDKCache;
import com.netease.nimlib.net.http.util.NosUtil;
import com.netease.nimlib.sdk.nos.model.NosThumbParam;

/**
 * 网易云信云存储图片缩略图URL生成工具
 */
public class NosThumbImageUtil {

    public static final String makeImageThumbUrl(String url, NosThumbParam.ThumbType thumb, int width, int height) {
        return NosUtil.appendQueryParams(url, toImageThumbParams(thumb, width, height));
    }

    public static final String makeImageThumbUrl(String url, int originW, int originH) {
        NosThumbParam.ThumbType thumb = NosThumbParam.ThumbType.Internal;
        if (originH > 0 && originW > 0) {
            int ration = (originW > originH ? originW / originH : originH / originW);
            thumb = ration > 4 ? NosThumbParam.ThumbType.External : NosThumbParam.ThumbType.Internal;
        }

        int width = SDKCache.getOptions().thumbnailSize;
        if (width <= 0) {
            DisplayMetrics dm = SDKCache.getContext().getApplicationContext().getResources().getDisplayMetrics();
            width = Math.min(dm.widthPixels, dm.heightPixels) / 2;
        }
        return NosUtil.appendQueryParams(url, toImageThumbParams(thumb, width, width));
    }

    private static final String toImageThumbParams(NosThumbParam.ThumbType thumb, int width, int height) {
        if (!checkImageThumb(thumb, width, height)) {
            throw new IllegalArgumentException("width=" + width + ", height=" + height);
        }

        StringBuilder sb = new StringBuilder();

        sb.append("thumbnail=");
        sb.append(width);
        sb.append(toImageThumbMethod(thumb));
        sb.append(height);

        sb.append("&imageView");

        return sb.toString();
    }

    private static final boolean checkImageThumb(NosThumbParam.ThumbType thumb, int width, int height) {
        // not allow negative
        if (width < 0 || height < 0) {
            return false;
        }

        switch (thumb) {
            case Internal:
                // not allow both zero
                return width > 0 || height > 0;
            case Crop:
            case External:
                // not allow either zero
                return width > 0 && height > 0;
        }

        return false;
    }

    private static final String toImageThumbMethod(NosThumbParam.ThumbType thumb) {
        switch (thumb) {
            case Internal:
                return "x";
            case Crop:
                return "y";
            case External:
                return "z";
        }

        throw new IllegalArgumentException("thumb: " + thumb);
    }
}