尝试使用 imagecreatefromstring 保存 base64 图像，它完全是黑色的

Posted 2023-02-25

【中文标题】尝试使用 imagecreatefromstring 保存 base64 图像，它完全是黑色的

【英文标题】：Trying to save base64 image using imagecreatefromstring and it is completely black

【发布时间】：2011-01-27 06:35:21

【问题描述】：

我正在尝试从数据库中获取 Base64 编码图像并将其保存到文件中。无论出于何种原因，当我尝试使用 imagecreatefromstring 和 imagepng 时，图像完全是黑色的。我尝试了许多不同的方法，但最终还是得到了一个黑匣子。下面是我让它工作的最佳尝试。有任何想法吗？提前非常感谢您！

$thefile = base64_decode($strImage);  
$img = imagecreatefromstring($thefile);  

if($img !== false)  

    header('Content-Type: image/png');  
    imagepng($img);  
    imagedestroy($img);   

这应该是上面的，但格式看起来不正确.... $ strImage ='iVBORw0KGgoAAAANSUhEUgAAA4QAAAD6CAYAAAD5jokXAAAMrUlEQVR4nO3dPahkZxkH8P + CkiqlaKGojcHCr9gEBBsbu5QiSRXBTksRsUijwcI0IorBD4gGGwvxC4soKLEQImiMRgMmMYmRGDbZbLJ7d ++ 9Zy3OPdzZ2bv3zuzMnOd8 / H4wxe4O8z4zmWL + ed73fRIAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABG4ukkzQmPgyQXkjxcVxoAAAC78kba8HeY5OrRY // oz4vhcL + qQAAAAHanOeXfPpe2U9gFw2d6qQgAAIBeXFvhOa9FtxAAAGByTusQLlvsFr68m3IAAADoyyodwkW6hQAAABOxTodwUdctPNxiLQAAAPRo3Q7hor0cdwtf3U45AAAA9GWTQJgkP48tpAAAAKN0q1tGl9lCCgAAMDKbdggXLW4h / d0WXxcAAIAd2GYgTI63kF5L8uaWXxsAAIAt2taW0WWHR6 + 9t6PXBwAAYEPb7hAuEgoBAAAGbJeBMBEKAQAABmtXW0YXCYUAAAADtOsOYUcoBAAAGJi + AmEiFAIAAAxKn4EwEQoBAAAGo48zhMu6UHi5YG0AAACO9N0h7HSh8N9F6wMAAMxeVSBM2kDYJPl4YQ0AAACzVRkIf5DjUAgAAEDPKgNhkryWNhAeFtcBAAAwO0Pozu2lreOguhAAAIA5qe4QdvbThsKr1YUAAADMxVACYdJ2CJskF6sLAQAAmIMhBcLEJTMAAAC9GVogvJw2EL5RXQgAAMDUDS0QJrqEAAAAO3d3hhm8Xk9b1151IQAAAFPWJLlUXcQJDjPMsAoAADBoz6e9sfPyCs9t0o58GJqnYwwFAADA2tYZ8t6k7cYNkS4hAADAmta5KGbIgfCBrBduAQAAZm + dQDj0Llw3rP5cdSEAAABjsE4g7ALXkA25iwkAADAo6wS8K2s + v0IXWr9fXQgAA MDQrXM7508z / ECY6BICAACsZN3wtM4W0ypdJ / Of1YUAAAAM2boXxYwhECa6hAAAAGda96KYsQTCMVyAAwAAUOrlrDeqYSyBMGnf1351EQAAAEO2zsUyYwqEQ5 + bOCUvpu3KfrFg7fMFawIAwGSsc95uTIHw2bTv7XJxHXPRbdP9bc / rCv0AALCBdTppYwqESfu + BIB + VHW / xvadBACAQdnPdAPhG2nf24PVhcyEQAgAACPzStrQ9LUVnjvGH99jrHmsBEIAABihVS + WGeP2S4GhP31 / P24vWBMAACZn1YtlxhiuxljzWFV81k2SbxWsCwAAk7HqxTJjDFdjrHmsqgLhcwXrAgDAZHQjA84yxnA1xprHquKzPkhypWBdAACYjO5imXNnPG + M4apJzcD0Oar4fpyPc4QAALCxVS6WGVsgvBphoU8V34 / fxH9jAADY2CoXy4wtEK56NpLNnUvNZ / 2BrNbdBgAATrFKeBpbIFz19lS2o0nyy6J1bQsGAIANXMk0A + FBdREz0iR5rWjdPxSsCwAAk9Ft + bt4ynPGFAj / nvb9uIGyP02S / YJ1D9JejAQAAGzgrI7aWM7j7cV20QpVn / nFnH0hEgAAcIYmp4e + MXQIhcE6VZ / 7UxnP / 6wAAIDBOmtA / dADoTBYq + PW1 + 8WrQsAAJPyatof1g / C5N + HHAi7S3GEwTpVgfD9MXoCAAC24rSLQYYaCA / S1uZG0***dZh3qUnyzaK1AQBgMk7rsg0tEF7N8blHYbDepdQFwr0kzxetDQAAk3Fal2cogfBijoPgYZLP1JbDkb + mLhA + mZqRFwAAMCkX0v6of + SEf6sOhHfl + Jxa1RB0bu7DqQuEny9cGwAAJuVm5wirAuGFXB8EDZsfribJjwrX / mzR2gAAMBk3O0fYdyDcz3EIdE5wHJokLxWtvZ / kz0VrAwDAZNzsHGEfgXC5G3h49HeMQ5P2gpcKLya5XLQ2AABMxitpf9jfs / T3uwyEy91AF 4SMU2Un96E4RwgAAFvRpB0jsGjbgfBKdAOn5rSxJbt2 + 9H6dxatDwAAk3FSl24bgXA5BOoGTktlIOzW / 1Xh + gAAMAkn / bDfJBBezo0h8NwGr8cwdWG / yoUkrxauDwAAk7DtQJij17uW64PhWY / Do8dBkqtph9ILksNVHQgfTW2HEgAAJuGkH / bb2DL6Ztpgd9rjIMdBcJXQeJA2CFCvuxyoyl1H699WWAMAAIzeSaMnqgbTL / tS2gtv9nNjaDxMGyp1EWtcSP1NnwdJvlFcAwAAjNqVDDcQnuS5HIfY5YD4ZmFdc / PH1AfCZ9LOJAQAAG7Rf9L + SF / stA05EC67nJO7h8ujNNiud6c + EH4lzhECAMDGlkdCVP / Qv1V35sbB94dJni2sacqaJF8vXP8tRzV8srAGAAAYveWbRsfUIbyZ7 + XGraUHSe6tLGpimiR / K67hYpLHimsAAIBRW75YZgqBcNGF3Lit1IU0m2uSvF5cw6OxPRgAADbS3Rj5w6M / Ty0QLtrLjVtK7ymtaLy6YF3pQ0d1vLW4DgAAGLXFc4RTDoSLFs8bCobrW95qXOVSkvuqiwAAgDFb / HE / l0DYWTxrKBiubiiB8E9JflldBAAAjNniOcK5BcKOYLieoQTCryZ5uboIAAAYs1fS / SD / dOYbCDvLwfAfteUMVndRT7X3pK3jtuI6AABg1Jq0l67MPRB2FoPhleJahmgogTBxjhAAADbWzeoTCK / XBcOD6kIGZnlcSSXnCAEAYEPdFkmB8EbdjaRDODM3FJcynEDoHCEAAGxocXg7N1qcYWioffJChvNdeW / abb3mEQIAwC3qtgDqEN7cazkOhb8vrqXazzKcQJgkP07yheoiAABgrLotgALh6b6T41D4RHEtld6ZYQXCdyV5uLoIAAAYM4Fwdd1n9WZ1IYWaJN + uLgIAANgOgXA93bnLvepCijRJ / lVdBAAAsB0C4frmHAqbzLtDCgAAk2LsxK2Zayg0nxEAA CZEILx1cwyFZjMCAMCEXI1AuIludMcb1YX0RCAEAIAJeTxtIDR4 / dbNaRtl1xUFAAAmQodwM3MKSXN6rwAAMAsC4WauZj4h6Urm814BAGAWBMLNNWnD0tT9LwIhAABMikC4ublctvKbCIQAADApAuHmuttGp + 6OzON9AgDAbAiEm3skbVA6X11ID5okP6ouAgAAYEjmsm20SfJSdREAAABDMpeRDHO5QAcAAGBl59OGpU9VF7Jjc + mEAgAArKVJO5dwygRCAACAE8whLM1laywAAMBa5hCW9jP99wgAALC2OcwjvJDpv0cAAIC1PZo2LJ3rcc2 + u5KP9bweAADAaFzreb1Xel7z / rSB8O09rgkAADAKfQfCijXncHkOAADA2voOZ / EM / 22qvz5a84M9rgkAADB4FR3CJu3tn32qeJ8AAACDtZ + 6QNjnFs6fHK35iR7XBAAAGKQH0wakJsmVgvUrxl104yfu73ldAACAQbg7x2MfmiQvFNXxl6P1P1q0PgAAwGycy / VB8KC2nCTDqQMAAGBy7svx1swhBcFO3wPqAQAAJu1Sru8Edo ++ B / RcxVNpa / tIdSEAAABj8r4ke2k7ficFwMMkr5ZVt7omydXqIgAAgGn5Vdqw9LHqQjZ0IW1376TQtxwA95PcUVPmLet7 / AQAADATQwsb9yY5n3bMw36Ou3tnhb3F0NcFv9 / 3XPuuOEcIAADsxMW0Q9dXCVvVj8OFx0Ha0Pfk9j + SwamYRwgAAMzE + bRn1Cofe0me2PUbHalfpA2E76guBAAAgP4N9RZUAAAAdmxoZz0BAADoiXOEAAAAM / VQ2kD4tupCAAAA6N + 16gIAAACoIRACAADMlEAIAAAwUwIhAADATAmEAAAAMyUQAgAAzJQ5hAAAADP037SB8MvVhQAAANC / g7Sh8PHqQgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAbfo / R04U3Pjl9j8AAAAASUVORK5CYII ='; P>

【问题讨论】：

我会说和alpha通道有关，base64的内容很好，我用其他工具写出来的。

【参考方案1】：

在你的 imagepng() 之前调用 imagesavealpha()

imagesavealpha($img, true);
imagepng($img);

【讨论】：

谢谢！那行得通！昨晚我花了好几个小时把头撞在墙上试图弄清楚这一点。非常感谢您抽出宝贵时间回答

这是救命稻草 :)