iOS平台下尺寸适中的遮罩导致URLImage.createMaskAdapter等方法失效

近期发现Codename One在iOS平台出现回归问题：调用URLImage.createMaskAdapter()创建遮罩适配器时会失败，但相同代码在Codename One模拟器、Android设备上运行正常，且几天前iOS平台也能正常工作。

初步排查后排除了近期UIScene改动的影响。

复现细节 #

• 可正常运行的小尺寸遮罩代码：

Image roundMask = Image.createImage(100, 100, 0xff000000);
Graphics g = roundMask.getGraphics();
g.setColor(0xffffff);
g.fillRoundRect(0, 0, 100, 100, 60, 60);

URLImage.ImageAdapter ada = URLImage.createMaskAdapter(roundMask);

Image roundMask = Image.createImage(100, 150, 0xff000000);
Graphics g = roundMask.getGraphics();
g.setColor(0xffffff);
g.fillRoundRect(0, 0, 100, 150, 60, 60);

URLImage.ImageAdapter ada = URLImage.createMaskAdapter(roundMask);

• 运行失败的中等尺寸遮罩代码：

Image roundMask = Image.createImage(410, 410, 0xff000000);
Graphics g = roundMask.getGraphics();
g.setColor(0xffffff);
g.fillRoundRect(0, 0, 410, 410, 60, 60);

URLImage.ImageAdapter ada = URLImage.createMaskAdapter(roundMask);

Image roundMask = Image.createImage(410, 614, 0xff000000);
Graphics g = roundMask.getGraphics();
g.setColor(0xffffff);
g.fillRoundRect(0, 0, 410, 614, 60, 60);

URLImage.ImageAdapter ada = URLImage.createMaskAdapter(roundMask);

抛出的异常 #

[EDT] 0:0:0,963 - Exception: java.lang.RuntimeException - null
java.lang.RuntimeException
    at com_codename1_ui_Image.createMask:1090
    at com_codename1_ui_URLImage.createMaskAdapter:231

问题总结 #

问题出在iOS平台下Image.createMask()/URLImage.createMaskAdapter()处理中等尺寸遮罩的逻辑上。410×410这类尺寸并不算特别大，但该功能近期在iOS平台出现回归，此前可正常运行。

内容的提问来源于stack exchange，提问作者Carlos Verdier