简体中文（ZH-CN）English（EN）繁体中文（ZH-TW）日本語（JA）한국어（KO）
Home
Article
Q&A
Course
Topic
Download
Game
Dictionary

Home  >  Article  >  Backend Development  >  php generates image thumbnails (supports: JPEG, GIT, PNG, BMP)

php generates image thumbnails (supports: JPEG, GIT, PNG, BMP)

WBOY
WBOYOriginal
2016-07-25 08:45:091184browse
  1. class Thumb
  2. {
  4. public function create($srcPath, $dstPath, $dstWidth, $dstHeight)
  5. {
  6. if (!file_exists($srcPath)) {
  7. return false;
  8. }
  10. @$srcSize = getimagesize($srcPath);
  11. if (empty($srcSize)) {
  12. return false;
  13. }
  15. $srcWith = intval($srcSize[0]);
  16. $srcHeight = intval($srcSize [1]);
  18. //If the size of the original image is larger than the size of the specified thumbnail, generate a thumbnail, otherwise copy the original file
  19. if ($srcWith <= $dstWidth && $srcHeight <= $dstHeight) {
  20. return copy($srcPath, $dstPath);
  21. }
  23. //Read the original image resource
  24. @$srcImage = imagecreatefromjpeg($srcPath);
  25. if (empty($srcImage)) {
  26. @$srcImage = imagecreatefromgif( $srcPath);
  27. }
  28. if (empty($srcImage)) {
  29. @$srcImage = imagecreatefrompng($srcPath);
  30. }
  31. if (empty($srcImage)) {
  32. @$srcImage = $this->_imageCreateFromBMP ($srcPath);
  33. }
  35. if (empty($srcImage)) {
  36. return false;
  37. }
  39. //Get the size of the thumbnail and generate a new image accordingly
  40. $dstSize = $this-> _getDstSize(
  41. $srcWith, $srcHeight, $dstWidth, $dstHeight
  42. );
  44. @$dstImage = imagecreatetruecolor(
  45. $dstSize['width'], $dstSize['height']
  46. );
  48. @imagecopyresampled(
  49. $dstImage, $srcImage , 0, 0, 0, 0,
  50. $dstSize['width'], $dstSize['height'],
  51. $srcWith, $srcHeight
  52. );
  54. return @imagepng($srcPath, $ dstPath);
  55. }
  57. private function _imageCreateFromBMP($filePath)
  58. {
  59. $fileHandle = fopen($filePath, 'rb');
  60. if (empty($fileHandle)) {
  61. return false;
  62. }
  64. $file = unpack(
  65. 'vfile_type/Vfile_size/Vreserved/Vbitmap_offset',
  66. fread($fileHandle, 14)
  67. );
  69. if ($file['file_type'] != 19778) {
  70. return false;
  71. }
  73. $ bmp = unpack(
  74. 'Vheader_size/Vwidth/Vheight/vplanes/'.
  75. 'vbits_per_pixel/Vcompression/Vsize_bitmap/'.
  76. 'Vhoriz_resolution/Vvert_resolution/Vcolors_used/Vcolors_important',
  77. fread($fileHandle, 40)
  78. );
  79. $ bmp['colors'] = pow(2, $bmp['bits_per_pixel']);
  80. if ($bmp['size_bitmap'] == 0) {
  81. $bmp['size_bitmap'] = $file['file_size' ] - $file['bitmap_offset'];
  82. }
  83. $bmp['bytes_per_pixel'] = $bmp['bits_per_pixel'] / 8;
  84. $bmp['bytes_per_pixel2'] = ceil($bmp['bytes_per_pixel']) ;
  85. $bmp['decal'] = $bmp['width'] * $bmp['bytes_per_pixel'] / 4;
  86. $bmp['decal'] -= floor($bmp['width'] * $bmp ['bytes_per_pixel'] / 4);
  87. $bmp['decal'] = 4 - (4 * $bmp['decal']);
  88. if ($bmp['decal'] == 4) {
  89. $bmp ['decal'] = 0;
  90. }
  92. $palette = array();
  93. if ($bmp['colors'] < 16777216) {
  94. $palette = unpack(
  95. 'V' . $bmp['colors '],
  96. fread($fileHandle, $bmp['colors'] * 4)
  97. );
  98. }
  99. $image = fread($fileHandle, $bmp['size_bitmap']);
  100. $vide = chr(0) ;
  101. $res = imagecreatetruecolor($bmp['width'], $bmp['height']);
  102. $p = 0;
  104. $y = $bmp['height'] - 1;
  105. while ($y >= 0) {
  106. $x = 0;
  107. while ($x < $bmp['width']) {
  108. if ($bmp['bits_per_pixel'] == 24) {
  109. $color = unpack(' V', substr($image, $p, 3) . $vide);
  110. } else if ($bmp['bits_per_pixel'] == 16) {
  111. $color = unpack('n', substr($image, $p, 2));
  112. $color[1] = $palette[$color[1]+1];
  113. } else if ($bmp['bits_per_pixel'] == 8) {
  114. $color = unpack(' n', $vide . substr ($image, $p, 1));
  115. $color[1] = $palette[$color[1]+1];
  116. } else if ($bmp['bits_per_pixel'] = =4) {
  117. $color = unpack('n', $vide . substr($image, floor($p), 1));
  118. if (($p * 2) % 2 == 0) {
  119. $ color[1] = ($color[1] >> 4);
  120. } else {
  121. $color[1] = ($color[1] & 0x0F);
  122. }
  123. $color[1] = $palette [$color[1] + 1];
  124. }else if ($bmp['bits_per_pixel'] == 1) {
  125. $color = unpack('n', $vide . substr($image, floor($p), 1));
  126. switch (($p * 8) % 8) {
  127. case 0:
  128. $color[1] = ($color[1] >> 7);
  129. break;
  130. case 1:
  131. $color[1] = ($color[1] & 0x40) >> 6;
  132. break;
  133. case 2:
  134. $color[1] = ($color[1] & 0x20) >> 5;
  135. break;
  136. case 3:
  137. $color[1] = ($color[1] & 0x10) >> 4;
  138. break;
  139. case 4:
  140. $color[1] = ($color[1] & 0x8) >> 3;
  141. break;
  142. case 5:
  143. $color[1] = ($color[1] & 0x4) >> 2;
  144. break;
  145. case 6:
  146. $color[1] = ($color[1] & 0x2) >> 1;
  147. break;
  148. case 7:
  149. $color[1] = ($color[1] & 0x1);
  150. break;
  151. }
  152. $color[1] = $palette[$color[1] + 1];
  153. } else {
  154. return false;
  155. }
  156. imagesetpixel($res, $x, $y, $color[1]);
  157. $x++;
  158. $p += $bmp['bytes_per_pixel'];
  159. }
  160. $y--;
  161. $p += $bmp['decal'];
  162. }
  163. fclose($fileHandle);
  164. return $res;
  165. }
  167. private function _getDstSize($srcWith, $srcHeight, $dstWidth, $dstHeight)
  168. {
  169. $size = array('width' => $srcWith, 'height' => $srcHeight);
  170. if ($dstWidth > 0 && $dstHeight > 0) {
  171. if ($srcWith > 0 && $srcHeight > 0) {
  172. if ($srcWith / $srcHeight >= $dstWidth / $dstHeight) {
  173. if ($srcWith > $dstWidth) {
  174. $size['width'] = $dstWidth;
  175. $size['height'] = $srcHeight * $dstWidth / $srcWith;
  176. }
  177. } else {
  178. if ($srcHeight > $dstHeight) {
  179. $size['width'] = $srcWith * $dstHeight / $srcHeight;
  180. $size['height'] = $dstHeight;
  181. }
  182. }
  183. }
  184. }
  185. return $size;
  186. }
  187. }
复制代码

JPEG, php, GIT


Statement：
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Previous article：PHP file upload sample codeNext article：PHP file upload sample code

Related articles

See more