UIImageView 缩放图像问题
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【中文标题】UIImageView 缩放图像问题【英文标题】：UIImageView scaling image issue 【发布时间】：2016-09-04 23:00:17 【问题描述】：我有一个宽度远大于高度的 UIImage。我试图在保持纵横比的同时在 UIImageView 中显示它，但 imageview 只显示图像的一小部分。我做错了吗？
func scale(image:UIImage)
imageView.contentMode = UIViewContentMode.ScaleAspectFit
imageView.image = image
print(imageView.frame.size.width)
print(image.size.width)
在控制台打印出来：
250.0
3024.0
image.size.height 的值为 150。
我希望它看起来像这样
但它看起来像这样
【问题讨论】：
您希望它看起来如何？可以分享一些截图吗？ 为截图编辑了我的帖子 可能需要查看整个 View Controller 类。 您是从viewDidLoad 调用scale，如果是，请尝试从viewDidLayoutSubviews 调用它，而不是使用自动布局。
我没有使用自动布局。我的 UIImageView 仅居中对齐并设置为 600 宽度和 250 高度。
【参考方案1】：
我无法理解您的问题。你能展示更多的代码和故事板吗？
不管怎样，这里是研究问题的例子：
ViewController.swift
import UIKit
class ViewController: UIViewController
@IBOutlet var imageView: UIImageView!
override func viewDidLoad()
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
override func didReceiveMemoryWarning()
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
@IBAction func SelectImage(sender: UIButton)
switch sender.tag
case 0:
imageView.image = UIImage(named: "image1")
case 1:
imageView.image = UIImage(named: "image2")
default:
break
Main.storyboard
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="10117" systemVersion="15G31" targetRuntime="ios.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" initialViewController="mG9-Ie-ulu">
<dependencies>
<deployment identifier="iOS"/>
<plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="10085"/>
<capability name="Constraints to layout margins" minToolsVersion="6.0"/>
</dependencies>
<scenes>
<!--View Controller-->
<scene sceneID="phU-zf-Z59">
<objects>
<viewController id="e22-se-1BX" customClass="ViewController" customModule="***_39322193" customModuleProvider="target" sceneMemberID="viewController">
<layoutGuides>
<viewControllerLayoutGuide type="top" id="ieU-T4-sfY"/>
<viewControllerLayoutGuide type="bottom" id="pBS-7o-IXo"/>
</layoutGuides>
<view key="view" contentMode="scaleToFill" id="GUS-lS-q7w">
<rect key="frame" x="0.0" y="0.0" />
<autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
<subviews>
<imageView userInteractionEnabled="NO" contentMode="scaleAspectFit" horizontalHuggingPriority="251" verticalHuggingPriority="251" image="image1" translatesAutoresizingMaskIntoConstraints="NO" id="upT-By-1gT">
<rect key="frame" x="0.0" y="20" />
</imageView>
<button opaque="NO" tag="1" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="j8O-MB-VWm">
<rect key="frame" x="479" y="562" />
<state key="normal" title="Select Image 2"/>
<connections>
<action selector="SelectImage:" destination="e22-se-1BX" eventType="touchUpInside" id="uLd-Po-8ev"/>
</connections>
</button>
<button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="agx-9V-LpP">
<rect key="frame" x="20" y="562" />
<state key="normal" title="Select Image 1"/>
<connections>
<action selector="SelectImage:" destination="e22-se-1BX" eventType="touchUpInside" id="o9C-8u-JxX"/>
</connections>
</button>
</subviews>
<color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="calibratedWhite"/>
<constraints>
<constraint firstItem="agx-9V-LpP" firstAttribute="leading" secondItem="GUS-lS-q7w" secondAttribute="leadingMargin" id="Gx9-Lx-S7I"/>
<constraint firstAttribute="trailing" secondItem="upT-By-1gT" secondAttribute="trailing" id="Hji-6d-ORN"/>
<constraint firstAttribute="trailingMargin" secondItem="j8O-MB-VWm" secondAttribute="trailing" constant="-1" id="Jst-1T-PP4"/>
<constraint firstItem="agx-9V-LpP" firstAttribute="top" secondItem="upT-By-1gT" secondAttribute="bottom" constant="6" id="STt-vV-su8"/>
<constraint firstItem="agx-9V-LpP" firstAttribute="top" secondItem="j8O-MB-VWm" secondAttribute="top" id="Uhl-PA-XLU"/>
<constraint firstItem="upT-By-1gT" firstAttribute="leading" secondItem="GUS-lS-q7w" secondAttribute="leading" id="Xay-ar-ZB2"/>
<constraint firstItem="upT-By-1gT" firstAttribute="top" secondItem="GUS-lS-q7w" secondAttribute="top" constant="20" symbolic="YES" id="ZT9-p7-2vo"/>
<constraint firstItem="pBS-7o-IXo" firstAttribute="top" secondItem="agx-9V-LpP" secondAttribute="bottom" constant="8" symbolic="YES" id="cRT-De-cHc"/>
<constraint firstItem="agx-9V-LpP" firstAttribute="baseline" secondItem="j8O-MB-VWm" secondAttribute="baseline" id="zc4-Dn-9Iu"/>
</constraints>
</view>
<connections>
<outlet property="imageView" destination="upT-By-1gT" id="Z9C-40-UW3"/>
</connections>
</viewController>
<placeholder placeholderIdentifier="IBFirstResponder" id="Bqi-Ne-i08" userLabel="First Responder" sceneMemberID="firstResponder"/>
</objects>
<point key="canvasLocation" x="1116" y="517"/>
</scene>
<!--Root View Controller-->
<scene sceneID="ywS-Tj-ArZ">
<objects>
<tableViewController id="Ixy-MR-Jzp" sceneMemberID="viewController">
<tableView key="view" clipsSubviews="YES" contentMode="scaleToFill" alwaysBounceVertical="YES" dataMode="static" style="plain" separatorStyle="default" rowHeight="44" sectionHeaderHeight="28" sectionFooterHeight="28" id="qeH-hZ-NWL">
<rect key="frame" x="0.0" y="0.0" />
<autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
<color key="backgroundColor" white="1" alpha="1" colorSpace="calibratedWhite"/>
<sections>
<tableViewSection id="z96-NS-xWx">
<cells>
<tableViewCell clipsSubviews="YES" contentMode="scaleToFill" selectionStyle="default" indentationWidth="10" id="z9h-YZ-NYn">
<rect key="frame" x="0.0" y="64" />
<autoresizingMask key="autoresizingMask"/>
<tableViewCellContentView key="contentView" opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="center" tableViewCell="z9h-YZ-NYn" id="MBf-LU-nOF">
<rect key="frame" x="0.0" y="0.0" />
<autoresizingMask key="autoresizingMask"/>
<subviews>
<label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="show image" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="taK-E6-9Tb">
<rect key="frame" x="254" y="11" />
<fontDescription key="fontDescription" type="system" pointSize="17"/>
<color key="textColor" red="0.0" green="0.0" blue="0.0" alpha="1" colorSpace="calibratedRGB"/>
<nil key="highlightedColor"/>
</label>
</subviews>
<constraints>
<constraint firstItem="taK-E6-9Tb" firstAttribute="centerY" secondItem="MBf-LU-nOF" secondAttribute="centerY" id="Uxk-t1-uBI"/>
<constraint firstItem="taK-E6-9Tb" firstAttribute="centerX" secondItem="MBf-LU-nOF" secondAttribute="centerX" id="fqV-Xt-MGV"/>
</constraints>
</tableViewCellContentView>
<connections>
<segue destination="e22-se-1BX" kind="show" identifier="showImageView" id="fpv-Ij-HJm">
<nil key="action"/>
</segue>
</connections>
</tableViewCell>
</cells>
</tableViewSection>
</sections>
<connections>
<outlet property="dataSource" destination="Ixy-MR-Jzp" id="erF-5c-clc"/>
<outlet property="delegate" destination="Ixy-MR-Jzp" id="2Hw-QW-7TB"/>
</connections>
</tableView>
<navigationItem key="navigationItem" title="Root View Controller" id="Lrj-E3-lJl"/>
</tableViewController>
<placeholder placeholderIdentifier="IBFirstResponder" id="T9r-3a-rLA" userLabel="First Responder" sceneMemberID="firstResponder"/>
</objects>
<point key="canvasLocation" x="328" y="517"/>
</scene>
<!--Navigation Controller-->
<scene sceneID="hl3-CB-blQ">
<objects>
<navigationController id="mG9-Ie-ulu" sceneMemberID="viewController">
<navigationBar key="navigationBar" contentMode="scaleToFill" id="ZhA-OA-J4s">
<rect key="frame" x="0.0" y="0.0" />
<autoresizingMask key="autoresizingMask"/>
</navigationBar>
<connections>
<segue destination="Ixy-MR-Jzp" kind="relationship" relationship="rootViewController" id="h4s-cf-6cE"/>
</connections>
</navigationController>
<placeholder placeholderIdentifier="IBFirstResponder" id="it8-XA-fgK" userLabel="First Responder" sceneMemberID="firstResponder"/>
</objects>
<point key="canvasLocation" x="-492" y="517"/>
</scene>
</scenes>
<resources>
<image name="image1" />
</resources>
</document>
结果
要导入的图片
【讨论】：
您找到问题的解决方案了吗？以上是关于UIImageView 缩放图像问题的主要内容，如果未能解决你的问题，请参考以下文章
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