如何調整gd圖片的大小以適合其中寫入的文字？

Question

我想調整GD圖像的大小，以使其內容適合該圖像。

這顯然有可能嗎？

Answer 1

最大的問題是恢復文本的大小。 Imagettftext以及imagettfbox返回一個點數組，這些點描述了文本在圖像中的位置，但沒有一個區域，該區域使您可以在邏輯上使圖像適合它。

這是我的意思：

function demo($text, $size, $angle, $font)
{
    $gdh = imagecreatetruecolor(300, 300);
    $white = imagecolorallocate($gdh, 255, 255, 255);
    imagefill($gdh, 0, 0, $white);

    $black = imagecolorallocate($gdh, 0, 0, 0);
    $rect = imagettftext($gdh, $size, $angle, 50, 250, $black, $font, $text);

    // Display a rectangle using the teturn of imagettftext
    $red = imagecolorallocate($gdh, 255, 0, 0);
    imageline($gdh, $rect[0], $rect[1], $rect[2], $rect[3], $red);
    imageline($gdh, $rect[0], $rect[1], $rect[6], $rect[7], $red);
    imageline($gdh, $rect[2], $rect[3], $rect[4], $rect[5], $red);
    imageline($gdh, $rect[4], $rect[5], $rect[6], $rect[7], $red);

    // Calculate and display the real area we need to fit our image
    $blue = imagecolorallocate($gdh, 0, 0, 255);
    $minX = min(array ($rect[0], $rect[2], $rect[4], $rect[6]));
    $maxX = max(array ($rect[0], $rect[2], $rect[4], $rect[6]));
    $minY = min(array ($rect[1], $rect[3], $rect[5], $rect[7]));
    $maxY = max(array ($rect[1], $rect[3], $rect[5], $rect[7]));
    imageline($gdh, $minX, $minY, $minX, $maxY, $blue);
    imageline($gdh, $maxX, $minY, $maxX, $maxY, $blue);
    imageline($gdh, $minX, $minY, $maxX, $minY, $blue);
    imageline($gdh, $minX, $maxY, $maxX, $maxY, $blue);

    header("Content-type: image/png");
    imagepng($gdh);
    die();
} 

如果我們致電：

demo("Cheers!", 48, 45, "font.ttf");

我們將得到此圖像：

您可以以紅色看到imagettfbox給定的區域，以藍色看到計算所得的區域，這將使我們能夠定義適合文本的新圖像尺寸。

這是一種使文本適合圖像的解決方案（當然用您自己的字體替換font.ttf）。

function fitImageToText($gdh, $text, $size, $angle, $font)
{
    // Recover the box size where we will be able to put our text
    // Took from the doc http://www.php.net/manual/en/function.imagettfbbox.php#105593
    putenv('GDFONTPATH=' . realpath('.'));
    $rect = imagettfbbox($size, $angle, $font, $text);
    $minX = min(array ($rect[0], $rect[2], $rect[4], $rect[6]));
    $maxX = max(array ($rect[0], $rect[2], $rect[4], $rect[6]));
    $minY = min(array ($rect[1], $rect[3], $rect[5], $rect[7]));
    $maxY = max(array ($rect[1], $rect[3], $rect[5], $rect[7]));
    $targetWidth = $maxX - $minX;
    $targetHeight = $maxY - $minY;
    $srcWidth = imagesx($gdh);
    $srcHeight = imagesy($gdh);

    // Creating target image
    $targetGdh = imagecreatetruecolor($targetWidth, $targetHeight);
    imagealphablending($targetGdh, false);
    imagesavealpha($targetGdh, true);
    imagecopyresampled($targetGdh, $gdh, 0, 0, 0, 0, $targetWidth, $targetHeight, $srcWidth, $srcHeight);

    // Writting text inside the new image
    $red = imagecolorallocate($targetGdh, 255, 0, 0);
    imagettftext($targetGdh, $size, $angle, abs($minX), abs($minY), $red, $font, $text);

    return $targetGdh;
}

稱之為：

$gdh = imagecreatefrompng("cheers.png");
$newGdh = fitImageToText($gdh, "Cheers!", 48, 45, "font.ttf");
imagedestroy($gdh);

// Outputs the image
header("Content-type: image/png");
imagepng($newGdh);
imagedestroy($newGdh);
die();

原始圖片：

結果圖片：

注意：您的源圖像的寬高比將適合文本大小，而無需任何邏輯。 如果要保留圖像的長寬比，可以使用以下方法：

function fitImageToText($gdh, $text, $size, $angle, $font)
{
    // Recover the box size where we will be able to put our text
    // Took from the doc http://www.php.net/manual/en/function.imagettfbbox.php#105593
    putenv('GDFONTPATH=' . realpath('.'));
    $rect = imagettfbbox($size, $angle, $font, $text);
    $minX = min(array ($rect[0], $rect[2], $rect[4], $rect[6]));
    $maxX = max(array ($rect[0], $rect[2], $rect[4], $rect[6]));
    $minY = min(array ($rect[1], $rect[3], $rect[5], $rect[7]));
    $maxY = max(array ($rect[1], $rect[3], $rect[5], $rect[7]));
    $targetWidth = $maxX - $minX;
    $targetHeight = $maxY - $minY;
    $srcWidth = imagesx($gdh);
    $srcHeight = imagesy($gdh);

    // Recovering new source image size respecting its aspect ratio
    $srcRatio = $srcWidth / $srcHeight;
    $targetRatio = $targetWidth / $targetHeight;
    if ($srcWidth <= $targetWidth && $srcHeight <= $targetHeight)
    {
        $imgTargetWidth = $srcWidth;
        $imgTargetHeight = $srcHeight;
    }
    else if ($targetRatio > $srcRatio)
    {
        $imgTargetWidth = (int) ($targetHeight * $srcRatio);
        $imgTargetHeight = $targetHeight;
    }
    else
    {
        $imgTargetWidth = $targetWidth;
        $imgTargetHeight = (int) ($targetHeight / $srcRatio);
    }

    // Creating target image
    $targetGdh = imagecreatetruecolor($targetWidth, $targetHeight);
    imagealphablending($targetGdh, false);
    imagesavealpha($targetGdh, true);
    imagecopyresampled($targetGdh, $gdh, 0, 0, 0, 0, $imgTargetWidth, $imgTargetHeight, $srcWidth, $srcHeight);

    // Writting text inside the new image
    $red = imagecolorallocate($targetGdh, 255, 0, 0);
    imagettftext($targetGdh, $size, $angle, abs($minX), abs($minY), $red, $font, $text);

    return $targetGdh;
}

這將導致：