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ImageKnife
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降采样适配 

Signed-off-by: tsm <2418639820@qq.com>
This commit is contained in:
tsm 2024-05-22 16:30:02 +08:00
parent 68fbe7ef51
commit 620abe6468
1 changed files with 7 additions and 60 deletions
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67
library/src/main/ets/components/imageknife/downsampling/DownsampleStartegy.ets
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@ -24,30 +24,13 @@ export class FitCenter implements BaseDownsampling {
//实现 getScaleFactor 方法
getScaleFactor(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number): number {
const IS_BITMAP_FACTORY_SCALING_SUPPORTED = false; //这里需要根据实际情况设置这个值
if (IS_BITMAP_FACTORY_SCALING_SUPPORTED) {
const widthPercentage = requestedWidth / sourceWidth
const heightPercentage = requestedHeight / sourceHeight
return Math.min(widthPercentage, heightPercentage)
} else {
//类似 AT_LEAST,但只要求一个维度或另一个维度大于等于请求的尺寸
const maxIntegerFactor = Math.max(sourceHeight / requestedHeight, sourceWidth / requestedWidth);
const a = maxIntegerFactor === 0 ? 1 : 1 / highestOneBit(maxIntegerFactor)
return a;
}
const maxIntegerFactor = Math.max(sourceHeight / requestedHeight, sourceWidth / requestedWidth);
const a = maxIntegerFactor === 0 ? 1 : 1 / highestOneBit(maxIntegerFactor)
return a;
}
//实现 getSampleSizeRounding 方法
getSampleSizeRounding(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number): number {
const IS_BITMAP_FACTORY_SCALING_SUPPORTED = true; //这里需要根据实际情况设置这个值
// if (!IS_BITMAP_FACTORY_SCALING_SUPPORTED) {
// return 0;
// } else {
// TODO: 这个逻辑可能不正确，但是如果不这样做，我们可能会跳过一个采样尺寸，因为 QUALITY 更喜欢宽度和高度缩放因子中比较小的那个
// MEMORY 折中方案,他让我们更喜欢两者中较大的那个
//
// }
return SampleSizeRounding.MEMORY;
}
}
@ -131,16 +114,10 @@ export class AtMost implements BaseDownsampling {
const maxIntegerFactor = Math.ceil(Math.max(sourceHeight / requestedHeight, sourceWidth / requestedWidth));
let lesserOrEqualSampleSize = Math.max(1, highestOneBit(maxIntegerFactor));
let greaterOrEqualSampleSize = lesserOrEqualSampleSize
// if (lesserOrEqualSampleSize < maxIntegerFactor) {
// let greaterOrEqualSampleSize = lesserOrEqualSampleSize <<= 1; // lest shift by 1
// }
greaterOrEqualSampleSize = lesserOrEqualSampleSize << (lesserOrEqualSampleSize < maxIntegerFactor ? 1 : 0)
//返回缩放因子
return 1 / greaterOrEqualSampleSize
}
//实现 getSampleSizeRounding 方法
getSampleSizeRounding(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestHeight: number): SampleSizeRounding {
//根据 AtMost 的逻辑，总是返回 MEMORY
@ -159,25 +136,15 @@ export class CenterInside implements BaseDownsampling {
getScaleFactor(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number): number {
//获取 FIT_CENTER 的缩放因子
const fitCenterScaleFactor: ESObject = this.getScale(sourceWidth, sourceHeight, requestedWidth, requestedHeight);
//实现 getScaleFactor 方法
//返回不超过 1 的缩放因子，即尽量缩小图像以适应目标尺寸，但不会放大
return Math.min(1, fitCenterScaleFactor);
}
getScale(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number): number {
const IS_BITMAP_FACTORY_SCALING_SUPPORTED = false; //这里需要根据实际情况设置这个值
if (IS_BITMAP_FACTORY_SCALING_SUPPORTED) {
const widthPercentage = requestedWidth / sourceWidth
const heightPercentage = requestedHeight / sourceHeight
return Math.min(widthPercentage, heightPercentage)
} else {
//类似 AT_LEAST,但只要求一个维度或另一个维度大于等于请求的尺寸
const maxIntegerFactor = Math.max(sourceHeight / requestedHeight, sourceWidth / requestedWidth);
return maxIntegerFactor === 0 ? 1 : 1 / highestOneBit(maxIntegerFactor);
}
//类似 AT_LEAST
const maxIntegerFactor = Math.max(sourceHeight / requestedHeight, sourceWidth / requestedWidth);
return maxIntegerFactor === 0 ? 1 : 1 / highestOneBit(maxIntegerFactor);
}
@ -190,27 +157,7 @@ export class CenterInside implements BaseDownsampling {
//否则，使用 FIL_CENTER 的 SampleSizeRounding 值
return this.getSampleSize(sourceWidth, sourceHeight, requestedWidth, requestedHeight);
}
//实现 getSampleSizeRounding 方法
getSampleSize(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number): SampleSizeRounding {
const IS_BITMAP_FACTORY_SCALING_SUPPORTED = true; //这里需要根据实际情况设置这个值
if (IS_BITMAP_FACTORY_SCALING_SUPPORTED) {
return 0;
} else {
// TODO: 这个逻辑可能不正确，但是如果不这样做，我们可能会跳过一个采样尺寸，因为 QUALITY 更喜欢宽度和高度缩放因子中比较小的那个
// MEMORY 折中方案,他让我们更喜欢两者中较大的那个
//
// }
return SampleSizeRounding.MEMORY;
}
return SampleSizeRounding.MEMORY;
}
}
export enum DownsampleStrategy {
AT_LEAST,
AT_MOST,
FIT_CENTER,
CENTER_INSIDE,
CENTER_OUTSIDE,
NONE,
}