如何在 as3 中平滑图像的“缩放”和“平移”

Posted 2023-02-16

【中文标题】如何在 as3 中平滑图像的“缩放”和“平移”

【英文标题】：How to smooth 'zoom' and 'pan' of image in as3

【发布时间】：2019-01-15 07:34:08

【问题描述】：

我在 Adob​​e Animate 中使用 ActionScript 3 来缩放和平移绘图。每当单击控制面板中的中心按钮时，图像不会出现在中心，它会出现在下方..

Example of how photo inside MovieClip is not centred to the stage。

此外，平移和缩放也不流畅。我正在使用的代码是创建图像的视频剪辑，并且有一个控制面板来控制缩放和平移。请告诉我为使其顺利和可行所需的更改。

AS3代码如下：

import flash.events.MouseEvent;
import flash.events.Event;

var moveSpeed: Number = 5;
var sizeScale: Number = 0.04;
var clickMore: Boolean = false;
var clickLess: Boolean = false;
var clickLeft: Boolean = false;
var clickRight: Boolean = false;
var clickUp: Boolean = false;
var clickDown: Boolean = false;
var clickCenter: Boolean = false;

// --- 点击放大更多：

btMore.addEventListener(MouseEvent.MOUSE_DOWN, moreZoom);
function moreZoom(event: MouseEvent): void 
 clickMore = true;

btMore.addEventListener(MouseEvent.MOUSE_UP, stopMoreZoom);
function stopMoreZoom(event: MouseEvent): void 
 clickMore = false;

// --- 点击缩小：

btLess.addEventListener(MouseEvent.MOUSE_DOWN, lessZoom);
function lessZoom(event: MouseEvent): void 
 clickLess = true;

btLess.addEventListener(MouseEvent.MOUSE_UP, stopLessZoom);
function stopLessZoom(event: MouseEvent): void 
 clickLess = false;

// --- 点击左移：

btLeft.addEventListener(MouseEvent.MOUSE_DOWN, leftMove);
function leftMove(event: MouseEvent): void 
 clickLeft = true;

btLeft.addEventListener(MouseEvent.MOUSE_UP, stopLeftMove);
function stopLeftMove(event: MouseEvent): void 
 clickLeft = false;

// --- 点击向右移动：

btRight.addEventListener(MouseEvent.MOUSE_DOWN, rightMove);
function rightMove(event: MouseEvent): void 
 clickRight = true;

btRight.addEventListener(MouseEvent.MOUSE_UP, stopRightMove);
function stopRightMove(event: MouseEvent): void 
 clickRight = false;

// --- 点击上移：

btUp.addEventListener(MouseEvent.MOUSE_DOWN, upMove);
function upMove(event: MouseEvent): void 
 clickUp = true;

btUp.addEventListener(MouseEvent.MOUSE_UP, stopUpMove);
function stopUpMove(event: MouseEvent): void 
 clickUp = false;

// --- 点击下移：

btDown.addEventListener(MouseEvent.MOUSE_DOWN, downMove);
function downMove(event: MouseEvent): void 
 clickDown = true;

btDown.addEventListener(MouseEvent.MOUSE_UP, stopDownMove);
function stopDownMove(event: MouseEvent): void 
 clickDown = false;

// --- 点击移动中心：

btCenter.addEventListener(MouseEvent.MOUSE_DOWN, centerMove);
function centerMove(event: MouseEvent): void 
 clickCenter = true;

btCenter.addEventListener(MouseEvent.MOUSE_UP, stopCenterMove);
function stopCenterMove(event: MouseEvent): void 
 clickCenter = false;

// --- 点击缩放轮：

stage.addEventListener(MouseEvent.MOUSE_WHEEL, handleMouseWheel);
function handleMouseWheel(event: MouseEvent): void 
 if (myMCimg.scaleX >= 1) 
 myMCimg.scaleX += (event.delta * sizeScale);
 myMCimg.scaleY += (event.delta * sizeScale);
  else 
 myMCimg.scaleX = 1;
 myMCimg.scaleY = 1;
 

// --- 动作：

addEventListener(Event.ENTER_FRAME, enterFrame);
function enterFrame(event: Event): void 
 if (clickMore == true) 
 myMCimg.scaleX += sizeScale;
 myMCimg.scaleY += sizeScale;
 
 if ((clickLess == true) && (myMCimg.scaleX >= 1)) 
 myMCimg.scaleX -= sizeScale;
 myMCimg.scaleY -= sizeScale;
 
 if (clickLeft == true) 
 myMCimg.x -= moveSpeed;
 
 if (clickRight == true) 
 myMCimg.x += moveSpeed;
 
 if (clickUp == true) 
 myMCimg.y -= moveSpeed;
 
 if (clickDown == true) 
 myMCimg.y += moveSpeed;
 
 if (clickCenter == true) 

// --- 集中化：

 myMCimg.scaleX = 1;
 myMCimg.scaleY = 1;
 myMCimg.x = stage.stageWidth / 2;
 myMCimg.y = stage.stageHeight / 2;
 

// --- 点击键方向键盘：

stage.addEventListener(KeyboardEvent.KEY_DOWN, pressKeys);
function pressKeys(event: KeyboardEvent): void 

 if (event.keyCode == Keyboard.LEFT) 
 myMCimg.x -= moveSpeed;
 
 if (event.keyCode == Keyboard.RIGHT) 
 myMCimg.x += moveSpeed;
 
 if (event.keyCode == Keyboard.UP) 
 myMCimg.y -= moveSpeed;
 
 if (event.keyCode == Keyboard.DOWN) 
 myMCimg.y += moveSpeed;
 
 if (event.keyCode == Keyboard.ENTER) 

// --- 集中化：

 myMCimg.scaleX = 1;
 myMCimg.scaleY = 1;
 myMCimg.x = stage.stageWidth / 2;
 myMCimg.y = stage.stageHeight / 2;
 

// --- 点击拖动：

 myMCimg.addEventListener(MouseEvent.MOUSE_DOWN, dragMove);
 function dragMove(event: MouseEvent): void 
 myMCimg.startDrag();

 myMCimg.addEventListener(MouseEvent.MOUSE_UP, stopDragMove);
 function stopDragMove(event: MouseEvent): void 
 stopDrag();
 

【参考方案1】：

(1) 集中化：

要按宽度（水平）居中，也可以尝试减去图片的半宽度，例如：

myMCimg.x = (stage.stageWidth / 2) - (myMCimg.width / 2);

按高度集中的相同逻辑（垂直）。

(2) 缩放：

至于平滑缩放，我没有测试你的代码，所以不确定视觉问题 “不平滑” 到底是什么意思。也许这是你的输出设置？如果您尝试以下 3 个硬件加速选项：无、直接和 GPU ?

最后，我只能建议您尝试以下类似的方法作为替代方案（也许会有所帮助）：

要测试代码...

在舞台上创建 2 个不同的颜色框。

将每个框转换为 MovieClip（而不是按钮）。

为每个框指定一个实例名称（例如：zoom_in 和zoom_out）。

将图像添加/转换为具有 instance 名称 pic 的某些 MovieClip。

第一个示例将通过鼠标悬停更新缩放...

zoom_in.addEventListener(MouseEvent.MOUSE_OVER, process_zoom_rollover);
zoom_in.addEventListener(MouseEvent.MOUSE_OUT, process_zoom_rollout);

zoom_out.addEventListener(MouseEvent.MOUSE_OVER, process_zoom_rollover);
zoom_out.addEventListener(MouseEvent.MOUSE_OUT, process_zoom_rollout);

//# mouse pointer is placed over either zoom-in or zoom-out icon..
function process_zoom_rollover (event: MouseEvent): void 
 
    //trace("event.currentTarget : " + event.currentTarget.name );
    event.currentTarget.addEventListener(Event.ENTER_FRAME, animate_Zoom);


//# mouse pointer is now move away from over any zoom icon.
function process_zoom_rollout (event: MouseEvent): void 
 
    event.currentTarget.removeEventListener(Event.ENTER_FRAME, animate_Zoom);


function animate_Zoom (event:MouseEvent) : void 

    //# scale by PERCENTAGE (width or height / 100), then multiply by some SPEED amount
    if (event.currentTarget.name == "zoom_in") //increase width and height
     pic.width += ((pic.width /100 ) * 1.75); pic.height += ((pic.height /100 ) * 1.75);  

    if (event.currentTarget.name == "zoom_out") //decrease width and height
     pic.width -= ((pic.width /100 ) * 1.75); pic.height -= ((pic.height /100 ) * 1.75);  

第二个示例将通过鼠标点击更新缩放...

zoom_in.addEventListener(MouseEvent.CLICK, process_zoom_click);
zoom_out.addEventListener(MouseEvent.CLICK, process_zoom_click);

//# mouse pointer is placed over either zoom-in or zoom-out icon.
function process_zoom_click (event:MouseEvent) : void 
 
    //trace("event.currentTarget : " + event.currentTarget.name );
    if (event.currentTarget.name == "zoom_in") //increase width and height
     pic.width += ((pic.width /100 ) * 1.75); pic.height += ((pic.height /100 ) * 1.75);  

    if (event.currentTarget.name == "zoom_out") //decrease width and height
     pic.width -= ((pic.width /100 ) * 1.75); pic.height -= ((pic.height /100 ) * 1.75);